\input texinfo @c -*-texinfo-*-
-@c $Id: tinc.texi,v 1.8.4.8 2000/11/24 14:13:51 zarq Exp $
+@c $Id: tinc.texi,v 1.8.4.13 2001/01/17 01:40:46 zarq Exp $
@c %**start of header
@setfilename tinc.info
@settitle tinc Manual
This is the info manual for tinc, a Virtual Private Network daemon.
-Copyright @copyright{} 1998,199,2000 Ivo Timmermans
+Copyright @copyright{} 1998-2001 Ivo Timmermans
<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.8 2000/11/24 14:13:51 zarq Exp $
+$Id: tinc.texi,v 1.8.4.13 2001/01/17 01:40:46 zarq Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
@page
@vskip 0pt plus 1filll
@cindex copyright
-Copyright @copyright{} 1998,1999,2000 Ivo Timmermans
+Copyright @copyright{} 1998-2001 Ivo Timmermans
<itimmermans@@bigfoot.com>, Guus Sliepen <guus@@sliepen.warande.net> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.8 2000/11/24 14:13:51 zarq Exp $
+$Id: tinc.texi,v 1.8.4.13 2001/01/17 01:40:46 zarq Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
This tunneling allows VPN sites to share information with each other
over the Internet without exposing any information to others.
-This document is the manual for tinc. Included are chapters on how to
+This document is the manual for tinc. Included are chapters on how to
configure your computer to use tinc, as well as the configuration
process of tinc itself.
@cindex VPN
A Virtual Private Network or VPN is a network that can only be accessed
-by a few elected computers that participate. This goal is achievable in
+by a few elected computers that participate. This goal is achievable in
more than just one way.
@cindex private
-Private networks can consist of a single stand-alone ethernet LAN. Or
-even two computers hooked up using a null-modem cable. In these cases,
+Private networks can consist of a single stand-alone ethernet LAN. Or
+even two computers hooked up using a null-modem cable. In these cases,
it is
obvious that the network is @emph{private}, no one can access it from the
-outside. But if your computers are linked to the internet, the network
+outside. But if your computers are linked to the internet, the network
is not private anymore, unless one uses firewalls to block all private
-traffic. But then, there is no way to send private data to trusted
+traffic. But then, there is no way to send private data to trusted
computers on the other end of the internet.
@cindex virtual
-This problem can be solved by using @emph{virtual} networks. Virtual
-networks can live on top of other networks, but do not interfere with
-each other. Mostly, virtual networks appear like a singe LAN, even though
-they can span the entire world. But virtual networks can't be secured
+This problem can be solved by using @emph{virtual} networks. Virtual
+networks can live on top of other networks, but they use encapsulation to
+keep using their private address space so they do not interfere with
+each other. Mostly, virtual networks appear like a singe LAN, even though
+they can span the entire world. But virtual networks can't be secured
by using firewalls, because the traffic that flows through it has to go
through the internet, where other people can look at it.
-When one introduces encryption, we can form a true VPN. Other people may
+When one introduces encryption, we can form a true VPN. Other people may
see encrypted traffic, but if they don't know how to decipher it (they
need to know the key for that), they cannot read the information that flows
-through the VPN. This is what tinc was made for.
+through the VPN. This is what tinc was made for.
@cindex virtual
tinc uses normal IP datagrams to encapsulate data that goes over the VPN
-network link. In this case it's also clear that the network is
+network link. In this case it's also clear that the network is
@emph{virtual}, because no direct network link has to exist between to
participants.
-As is the case with either type of VPN, anybody could eavesdrop. Or
-worse, alter data. Hence it's probably advisable to encrypt the data
+As is the case with either type of VPN, anybody could eavesdrop. Or
+worse, alter data. Hence it's probably advisable to encrypt the data
that flows over the network.
@cindex vpnd
@cindex ethertap
I really don't quite remember what got us started, but it must have been
-Guus' idea. He wrote a simple implementation (about 50 lines of C) that
+Guus' idea. He wrote a simple implementation (about 50 lines of C) that
used the @emph{ethertap} device that Linux knows of since somewhere
-about kernel 2.1.60. It didn't work immediately and he improved it a
-bit. At this stage, the project was still simply called @samp{vpnd}.
+about kernel 2.1.60. It didn't work immediately and he improved it a
+bit. At this stage, the project was still simply called @samp{vpnd}.
Since then, a lot has changed---to say the least.
runtime-configurable---in short, it has become a full-fledged
professional package.
-A lot can---and will be---changed. I have a few things that I'd like to
-see in the future releases of tinc. Not everything will be available in
-the near future. Our first objective is to make tinc work perfectly as
+A lot can---and will be---changed. We have a number of things that we would like to
+see in the future releases of tinc. Not everything will be available in
+the near future. Our first objective is to make tinc work perfectly as
it stands, and then add more advanced features.
-Meanwhile, we're always open-minded towards new ideas. And we're
+Meanwhile, we're always open-minded towards new ideas. And we're
available too.
@node Supported platforms, , tinc, Introduction
@section Supported platforms
-tinc works on Linux, FreeBSD and Solaris. These are the three platforms
+tinc has been verified to work under Linux, FreeBSD and Solaris, with
+various hardware architectures. These are the three platforms
that are supported by the universial TUN/TAP device driver, so if
support for other operating systems is added to this driver, perhaps
tinc will run on them as well. Without this driver, tinc will most
likely compile and run, but it will not be able to send or receive data
packets.
-For a more up to date list, please check the list on our website:
+For an up to date list of supported platforms, please check the list on
+our website:
@uref{http://tinc.nl.linux.org/platforms.html}.
this is the best supported platform. The protocol however, and actually
anything about tinc, has been rewritten to support random byte ordering
and arbitrary word length. So in theory it should run on other
-processors that Linux runs on. Take care however, we haven't been able
-to really test it yet. If you want to run tinc on another platform than
-x86, and want to tell us how it went, please do so.
+processors that Linux runs on. It has already been verified to run on
+alpha and sparc processors as well.
tinc uses the ethertap device that is provided in the standard kernel
-since version 2.1.60, so anything above that (2.2.x, 2.3.x, and the
-2.4.0-testx (which is current at the time of this writing) kernel
-versions) is able to support tinc.
+since version 2.1.60, so anything above that (2.2.x, 2.3.x, and 2.4.0)
+kernel version is able to support tinc.
@c ==================================================================
@subsection Configuring the Linux kernel
Since this particular implementation only runs on 2.1 or higher Linux
-kernels, you should grab one (2.2 is current at this time). A 2.0 port
+kernels, you should grab one (2.2 is current at this time). A 2.0 port
is not really possible, unless someone tells me someone ported the
ethertap and netlink devices back to 2.0.
If you are unfamiliar with the process of configuring and compiling a
new kernel, you should read the
@uref{http://howto.linuxberg.com/LDP/HOWTO/Kernel-HOWTO.html, Kernel
-HOWTO} first. Do that now!
+HOWTO} first. Do that now!
Here are the options you have to turn on when configuring a new
kernel.
<*> Ethertap network tap
@end example
+Note that if you want to run more than one instance of tinc or other
+programs that use the ethertap, you have to compile the ethertap driver
+as a module.
+
For kernel 2.3.x and 2.4.x:
@example
@end example
-Any other options not mentioned here are not relevant to tinc. If you
+Any other options not mentioned here are not relevant to tinc. If you
decide to build any of these as dynamic kernel modules, it's a good idea
to add these lines to @file{/etc/modules.conf}.
alias char-major-36 netlink_dev
@end example
-If you have a 2.4 kernel, you can also choose to use the `Ethertap
-network tap' device. This is marked obsolete, because the universal
-TUN/TAP driver is a newer implementation that is supposed to be used in
-favor of ethertap. For tinc, it doesn't really matter which one you
-choose; based on the device file name, tinc will make the right choice
-about what protocol to use.
+If you have a 2.4-pre kernel, you can choose both the TUN/TAP driver and
+the `Ethertap network tap' device. This latter is marked obsolete,
+because the universal TUN/TAP driver is a newer implementation that is
+supposed to be used in favour of ethertap. For tinc, it doesn't really
+matter which one you choose; based on the device file name, tinc will make
+the right choice about what protocol to use. However, chances are that
+although you can choose the obsolote ethertap driver, it will not function
+at all. The TUN/TAP driver is the safe choice.
Finally, after having set up other options, build the kernel and boot
it. Unfortunately it's not possible to insert these modules in a
@end example
+@subsubheading License
+
+Since the license under which OpenSSL is distributed is not directly
+compatible with the terms of the GNU GPL
+@uref{http://www.openssl.org/support/faq.html#LEGAL2}, therefore we
+include an addition to the GPL (see also the file COPYING.README):
+
+@quotation
+This program is released under the GPL with the additional exemption
+that compiling, linking, and/or using OpenSSL is allowed. You may
+provide binary packages linked to the OpenSSL libraries, provided that
+all other requirements of the GPL are met.
+@end quotation
+
+
@c
@c
@c
the checksums of these files listed; you may wish to check these with
md5sum before continuing.
-tinc comes in a handy autoconf/automake package, which you can just
-treat the same as any other package. Which is just untar it, type
+tinc comes in a convenient autoconf/automake package, which you can just
+treat the same as any other package. Which is just untar it, type
`configure' and then `make'.
More detailed instructions are in the file @file{INSTALL}, which is
@node System files, Interfaces, Building tinc, Installing tinc - installation
@section System files
-Before you can run tinc, you
+Before you can run tinc, you must make sure you have all the needed
+files on your system.
@menu
* Device files::
@subsubheading @file{/etc/networks}
You may add a line to @file{/etc/networks} so that your VPN will get a
-symbolic name. For example:
+symbolic name. For example:
@example
myvpn 10.0.0.0
@subsubheading @file{/etc/services}
-You may add this line to @file{/etc/services}. The effect is that you
-may supply a @samp{tinc} as a valid port number to some programs. The
+You may add this line to @file{/etc/services}. The effect is that you
+may supply a @samp{tinc} as a valid port number to some programs. The
number 655 is registered with the IANA.
@example
tinc}.
It doesn't matter much which part you do first, setting up the network
-devices or configure tinc. But they both have to be done before you try
+devices or configure tinc. But they both have to be done before you try
to start a tincd.
The actual setup of the ethertap device is quite simple, just repeat
* Multiple networks::
* How connections work::
* Configuration file::
+* Required directives::
* Example::
@end menu
However, in its default form, you will soon notice that you can't use
two different configuration files without the -c option.
-We have thought of another way of dealing with this: network names. This
+We have thought of another way of dealing with this: network names. This
means that you call tincd with the -n argument, which will assign a name
to this daemon.
The effect of this is that the daemon will set its configuration
``root'' to /etc/tinc/nn/, where nn is your argument to the -n
-option. You'll notice that it appears in syslog as ``tinc.nn''.
+option. You'll notice that it appears in syslog as ``tinc.nn''.
However, it is not strictly necessary that you call tinc with the -n
-option. In this case, the network name would just be empty, and it will
-be used as such. tinc now looks for files in /etc/tinc/, instead of
+option. In this case, the network name would just be empty, and it will
+be used as such. tinc now looks for files in /etc/tinc/, instead of
/etc/tinc/nn/; the configuration file should be /etc/tinc/tinc.conf,
and the passphrases are now expected to be in /etc/tinc/passphrases/.
But it is highly recommended that you use this feature of tinc, because
-it will be so much clearer whom your daemon talks to. Hence, we will
+it will be so much clearer whom your daemon talks to. Hence, we will
assume that you use it.
Before going on, first a bit on how tinc sees connections.
When tinc starts up, it reads in the configuration file and parses the
-command-line options. If it sees a `ConnectTo' value in the file, it
-will try to connect to it, on the given port. If this fails, tinc exits.
+command-line options. If it sees a `ConnectTo' value in the file, it
+will try to connect to it, on the given port. If this fails, tinc exits.
@c ==================================================================
-@node Configuration file, Example, How connections work, Configuring tinc
+@node Configuration file, Required directives, How connections work, Configuring tinc
@section Configuration file
The actual configuration of the daemon is done in the file
@end example
The variable names are case insensitive, and any spaces, tabs, newlines
-and carriage returns are ignored. Note: it is not required that you put
+and carriage returns are ignored. Note: it is not required that you put
in the `=' sign, but doing so improves readability. If you leave it
out, remember to replace it with at least one space character.
+In this section all valid variables are listed in alphabetical order.
+The default value is given between parentheses; required directives are
+given in @strong{bold}.
+
@menu
-* Variables::
+* Main configuration variables::
+* Host configuration variables::
+* How to configure::
@end menu
-@c ==================================================================
-@node Variables, , Configuration file, Configuration file
-@subsection Variables
-Here are all valid variables, listed in alphabetical order. The default
-value, required or optional is given between parentheses.
+@c ==================================================================
+@node Main configuration variables, Host configuration variables, Configuration file, Configuration file
+@subsection Main configuration variables
-@c straight from the manpage
@table @asis
-@item ConnectPort = <port> (655)
-Connect to the upstream host (given with the ConnectTo directive) on
-port port. port may be given in decimal (default), octal (when preceded
-by a single zero) or hexadecimal (prefixed with 0x). port is the port
-number for both the UDP and the TCP (meta) connections.
-
-@item ConnectTo = <IP address|hostname> (optional)
-Specifies which host to connect to on startup. Multiple ConnectTo variables
-may be specified, if connecting to the first one fails then tinc will try
-the next one, and so on. It is possible to specify hostnames for dynamic IP
-addresses (like those given on dyndns.org), tinc will not cache the resolved
-IP address.
+@item @strong{ConnectTo = <name>}
+Specifies which host to connect to on startup. Multiple ConnectTo
+variables may be specified, if connecting to the first one fails then
+tinc will try the next one, and so on. It is possible to specify
+hostnames for dynamic IP addresses (like those given on dyndns.org),
+tinc will not cache the resolved IP address.
If you don't specify a host with ConnectTo, regardless of whether a
value for ConnectPort is given, tinc won't connect at all, and will
instead just listen for incoming connections.
@item Hostnames = <yes|no> (no)
-This option selects whether IP addresses (both real and on the VPN) should
-be resolved. Since DNS lookups are blocking, it might affect tinc's
-efficiency, even stopping the daemon for a few seconds everytime it does
-a lookup if your DNS server is not responding.
-
-This does not affect resolving hostnames to IP addresses from the configuration
-file.
-
-@item IndirectData = <yes|no> (no)
-This option specifies whether other tinc daemons besides the one you
-specified with ConnectTo can make a direct connection to you. This is
-especially useful if you are behind a firewall and it is impossible
-to make a connection from the outside to your tinc daemon. Otherwise,
-it is best to leave this option out or set it to no.
-
-@item Interface = <device> (optional)
-If you have more than one network interface in your computer, tinc will by
-default listen on all of them for incoming connections. It is possible to
-bind tinc to a single interface like eth0 or ppp0 with this variable.
-
-@item InterfaceIP = <local address> (optional)
-If your computer has more than one IP address on a single interface (for example
-if you are running virtual hosts), tinc will by default listen on all of them for
-incoming connections. It is possible to bind tinc to a single IP address with
-this variable. It is still possible to listen on several interfaces at the same
-time though, if they share the same IP address.
+This option selects whether IP addresses (both real and on the VPN)
+should be resolved. Since DNS lookups are blocking, it might affect
+tinc's efficiency, even stopping the daemon for a few seconds everytime
+it does a lookup if your DNS server is not responding.
+
+This does not affect resolving hostnames to IP addresses from the
+configuration file.
+
+@item Interface = <device>
+If you have more than one network interface in your computer, tinc will
+by default listen on all of them for incoming connections. It is
+possible to bind tinc to a single interface like eth0 or ppp0 with this
+variable.
+
+@item InterfaceIP = <local address>
+If your computer has more than one IP address on a single interface (for
+example if you are running virtual hosts), tinc will by default listen
+on all of them for incoming connections. It is possible to bind tinc to
+a single IP address with this variable. It is still possible to listen
+on several interfaces at the same time though, if they share the same IP
+address.
@item KeyExpire = <seconds> (3600)
This option controls the time the encryption keys used to encrypt the data
-are valid. It is common practice to change keys at regular intervals to
+are valid. It is common practice to change keys at regular intervals to
make it even harder for crackers, even though it is thought to be nearly
impossible to crack a single key.
@item ListenPort = <port> (655)
-Listen on local port port. The computer connecting to this daemon should
+Listen on local port port. The computer connecting to this daemon should
use this number as the argument for his ConnectPort.
@item MyOwnVPNIP = <local address[/maskbits]> (required)
The local address is the number that the daemon will propagate to
-other daemons on the network when it is identifying itself. Hence this
+other daemons on the network when it is identifying itself. Hence this
will be the file name of the passphrase file that the other end expects
to find the passphrase in.
The local address is the IP address of the tap device, not the real IP
-address of the host running tincd. Due to changes in recent kernels, it
+address of the host running tincd. Due to changes in recent kernels, it
is also necessary that you make the ethernet (also known as MAC) address
equal to the IP address (see the example).
@item MyVirtualIP = <local address[/maskbits]>
This is an alias for MyOwnVPNIP.
+@item @strong{Name = <name>}
+This is a symbolic name for this connection. It can be anything
+
@item PingTimeout = <seconds> (5)
The number of seconds of inactivity that tinc will wait before sending a
-probe to the other end. If that other end doesn't answer within that
+probe to the other end. If that other end doesn't answer within that
same amount of seconds, the connection is terminated, and the others
will be notified of this.
-@item PrivateKey = <key>
-This is a sequence of hexadecimal numbers, as generated by ``tincd
---generate-keys''.
+@item @strong{PrivateKey = <key>}
+This is the RSA private key for tinc. However, for safety reasons it is
+advised to store private keys of any kind in separate files. This prevents
+accidental eavesdropping if you are editting the configuration file.
+
+@item PrivateKeyFile = <path>
+This is the full path name of the RSA private key file that was
+generated by ``tincd --generate-keys''. It must be a full path, not a
+relative directory.
@item PublicKey = <key>
-This is a sequence of hexadecimal numbers, as generated by ``tincd
---generate-keys''.
+This is the full path name of the RSA public key file that was generated
+by ``tincd --generate-keys''. It must be a full path, not a relative
+directory. (NOTE: In version 1.0pre3, this variable was used to give
+the key inline. This is no longer supported.)
+
+@item Subnet = <IP address/maskbits>
+This is the subnet range of all IP addresses that will be accepted by
+the host that defines it. Please be careful that no two subnets
+overlap. Every host @strong{must} have a different range of IP
+addresses that it can handle, otherwise you will see messages like
+`packet comes back to us'.
@item TapDevice = <device> (/dev/tap0)
-The ethertap device to use. Note that you can only use one device per
-daemon. The info pages of the tinc package contain more information
+The ethertap device to use. Note that you can only use one device per
+daemon. The info pages of the tinc package contain more information
about configuring an ethertap device for Linux.
@item TCPonly = <yes|no> (no, experimental)
If this variable is set to yes, then the packets are tunnelled over a TCP
-connection instead of a UDP connection. This is especially useful for those
+connection instead of a UDP connection. This is especially useful for those
who want to run a tinc daemon from behind a masquerading firewall, or if
-UDP packet routing is disabled somehow. This is experimental code,
+UDP packet routing is disabled somehow. This is experimental code,
try this at your own risk.
@item VpnMask = <mask> (optional)
-The mask that defines the scope of the entire VPN. This option is not used
+The mask that defines the scope of the entire VPN. This option is not used
by the tinc daemon itself, but can be used by startup scripts to configure
the ethertap devices correctly.
@end table
+@c ==================================================================
+@node Host configuration variables, How to configure, Main configuration variables, Configuration file
+@subsection Host configuration variables
+
+@table @asis
+@item @strong{Address = <IP address|hostname>}
+This variable is only required if you want to connect to this host. It
+must resolve to the external IP address where the host can be reached,
+not the one that is internal to the VPN.
+
+@item IndirectData = <yes|no> (no)
+This option specifies whether other tinc daemons besides the one you
+specified with ConnectTo can make a direct connection to you. This is
+especially useful if you are behind a firewall and it is impossible to
+make a connection from the outside to your tinc daemon. Otherwise, it
+is best to leave this option out or set it to no.
+
+@item Port = <port> (655)
+Connect to the upstream host (given with the ConnectTo directive) on
+port port. port may be given in decimal (default), octal (when preceded
+by a single zero) o hexadecimal (prefixed with 0x). port is the port
+number for both the UDP and the TCP (meta) connections.
+
+@item PublicKey = <key>
+This is the RSA public key for this host.
+
+@item PublicKeyFile = <path>
+This is the full path name of the RSA public key file that was generated
+by ``tincd --generate-keys''. It must be a full path, not a relative
+directory.
+
+Note that exactly @strong{one of the above two options} must be specified
+in each host configuration file, if you want to be able to establish a
+connection with that host.
+
+@item Subnet = <IP address/maskbits>
+This is the subnet range of all IP addresses that will be accepted by
+the host that defines it.
+
+The range must be contained in the IP address range of the tap device,
+not the real IP address of the host running tincd.
+
+maskbits is the number of bits set to 1 in the netmask part; for
+example: netmask 255.255.255.0 would become /24, 255.255.252.0 becomes
+/22. This conforms to standard CIDR notation as described in
+@uref{ftp://ftp.isi.edu/in-notes/rfc1519.txt, RFC1519}
+
+@item TCPonly = <yes|no> (no)
+If this variable is set to yes, then the packets are tunnelled over a
+TCP connection instead of a UDP connection. This is especially useful
+for those who want to run a tinc daemon from behind a masquerading
+firewall, or if UDP packet routing is disabled somehow. @emph{This is
+experimental code, try this at your own risk. It may not work at all.}
+@end table
+
+
+@c ==================================================================
+@node How to configure, , Host configuration variables, Configuration file
+@subsection How to configure
+
+@subsubheading Step 1. Creating the key files
+
+For each host, you have to create a pair of RSA keys. One key is your
+private key, which is only known to you. The other one is the public
+key, which you should copy to all hosts wanting to authenticate to you.
+
+
+@subsubheading Step 2. Configuring each host
+
+For every host in the VPN, you have to create two files. First there is
+the main configuration file, @file{/etc/tinc/vpn-name/tinc.conf}. In
+this file there should at least be three directives:
+
+@table @samp
+@item Name
+You should fill in the name of this host (or rather, the name of this
+leaf of the VPN). It can be called after the hostname, the physical
+location, the department, or the name of one of your boss' pets. It can
+be anything, as long as all these names are unique across the entire
+VPN.
+
+@item PrivateKey
+Fill in the full pathname to the file that contains the private RSA key.
+
+@item ConnectTo
+This is the name of the host that you want to connect to (not a DNS
+name, rather the name that is given with the Name parameter in that
+hosts tinc.conf). This is the upstream connection. If your computer is
+a central node, you might want to leave this out to make it stay idle
+until someone connects to it.
+@end table
+
+@cindex host configuration file
+Then you should create a file with the name you gave yourself in
+tinc.conf (the `Name' parameter), located in
+@file{/etc/tinc/vpn-name/hosts/}. In this file, which we call the
+`@emph{host configuration file}', only one variable is required:
+
+@table @samp
+@item Subnet
+The IP range that this host accepts as being `local'. All packets with
+a destination address that is within this subnet will be sent to us.
+@end table
+
+
+@subsubheading Step 3. Bringing it all together
+
+Now for all hosts that you want to create a direct connection to, -- you
+connect to them or they connect to you -- you get a copy of their host
+configuration file and their public RSA key.
+
+For each host configuration file, you add two variables:
+
+@table @samp
+@item Address
+Enter the IP address or DNS hostname for this host. This is only needed
+if you connect to this host.
+
+@item PublicKey
+Put the full pathname to this hosts public RSA key here.
+@end table
+
+When you did this, you should be ready to create your first connection.
+Pay attention to the system log, most errors will only be visible
+there. If you get an error, you can check @ref{Error messages}.
+
@c ==================================================================
-@node Example, , Configuration file, Configuring tinc
+@node Example, , Required directives, Configuring tinc
@section Example
-Imagine the following situation. An A-based company wants to connect
-three branch offices in B, C and D using the internet. All four offices
+@cindex example
+Imagine the following situation. An A-based company wants to connect
+three branch offices in B, C and D using the internet. All four offices
have a 24/7 connection to the internet.
-A is going to serve as the center of the network. B and C will connect
-to A, and D will connect to C. Each office will be assigned their own IP
+A is going to serve as the center of the network. B and C will connect
+to A, and D will connect to C. Each office will be assigned their own IP
network, 10.x.0.0.
@example
@end example
``gateway'' is the VPN IP address of the machine that is running the
-tincd. ``internet IP'' is the IP address of the firewall, which does not
+tincd. ``internet IP'' is the IP address of the firewall, which does not
need to run tincd, but it must do a port forwarding of TCP&UDP on port
655 (unless otherwise configured).
In this example, it is assumed that eth0 is the interface that points to
-the inner LAN of the office, although this could also be the same as the
-interface that leads to the internet. The configuration of the real
-interface is also shown as a comment, to give you an idea of how these
-example host is set up.
+the inner (physical) LAN of the office, although this could also be the
+same as the interface that leads to the internet. The configuration of
+the real interface is also shown as a comment, to give you an idea of
+how these example host is set up.
@subsubheading For A
@example
#ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
-ifconfig tap0 hw ether fe:fd:0a:01:36:01
+ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.1.54.1 netmask 255.0.0.0
@end example
and in /etc/tinc/tinc.conf:
@example
-TapDevice = /dev/tap0
-MyVirtualIP = 10.1.54.1/16
+Name = A
+PrivateKey = /etc/tinc/A.priv
VpnMask = 255.0.0.0
@end example
+On all hosts, /etc/tinc/hosts/A contains:
+
+@example
+Subnet = 10.1.0.0/16
+Address = 1.2.3.4
+PublicKey = /etc/tinc/hosts/A.pub
+@end example
+
+
@subsubheading For B
@example
#ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
-ifconfig tap0 hw ether fe:fd:0a:02:01:0c
+ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.2.1.12 netmask 255.0.0.0
@end example
and in /etc/tinc/tinc.conf:
@example
-TapDevice = /dev/tap0
-MyVirtualIP = 10.2.1.12/16
-ConnectTo = 1.2.3.4
+Name = B
+ConnectTo = A
+PrivateKey = /etc/tinc/B.priv
VpnMask = 255.0.0.0
@end example
Note here that the internal address (on eth0) doesn't have to be the
-same as on the tap0 device. Also, ConnectTo is given so that no-one can
+same as on the tap0 device. Also, ConnectTo is given so that no-one can
connect to this node.
+On all hosts, /etc/tinc/hosts/B:
+
+@example
+Subnet = 10.2.0.0/16
+Address = 2.3.4.5
+PublicKey = /etc/tinc/hosts/B.pub
+@end example
+
+
@subsubheading For C
@example
#ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
-ifconfig tap0 hw ether fe:fd:0a:03:45:fe
+ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.3.69.254 netmask 255.0.0.0
@end example
and in /etc/tinc/A/tinc.conf:
@example
-MyVirtualIP = 10.3.69.254/16
+Name = C
+ConnectTo = A
TapDevice = /dev/tap1
-ConnectTo = 1.2.3.4
-ListenPort = 2000
VpnMask = 255.0.0.0
@end example
C already has another daemon that runs on port 655, so they have to
-reserve another port for tinc. It can connect to other tinc daemons on
-the regular port though, so no ConnectPort variable is needed.
-They also use the netname to distinguish
-between the two. tinc is started with `tincd -n A'.
+reserve another port for tinc. It can connect to other tinc daemons on
+the regular port though, so no ConnectPort variable is needed. They
+also use the netname to distinguish between the two. tinc is started
+with `tincd -n A'.
+
+On all hosts, /etc/tinc/hosts/C:
+
+@example
+Subnet = 10.3.0.0/16
+Port = 2000
+PublicKey = /etc/tinc/hosts/C.pub
+@end example
+
@subsubheading For D
@end example
D will be connecting to C, which has a tincd running for this network on
-port 2000. Hence they need to put in a ConnectPort, but it doesn't need
+port 2000. Hence they need to put in a ConnectPort, but it doesn't need
to have a different ListenPort.
-@subsubheading Authentication
+@subsubheading Key files
-A, B, C and D all generate a passphrase with genauth 2048, the output is
-stored in /etc/tinc/passphrases/local, except for C, where it should be
-/etc/tinc/A/passphrases/local.
+A, B, C and D all have generate a public key with tincd -K, the output is
+stored in /etc/tinc/hosts/X.pub (where X is A, B or D), except for C,
+who stored it in /etc/tinc/A/hosts/C.pub.
-A stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.1.12
+A stores a copy of B's public key in /etc/tinc/hosts/B.pub
-A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+A stores a copy of C's public key in /etc/tinc/hosts/C.pub
-B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.54.1
+B stores a copy of A's public key in /etc/tinc/hosts/A.pub
-C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.54.1
+C stores a copy of A's public key in /etc/tinc/A/hosts/A.pub
-C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.3.32
+C stores a copy of D's public key in /etc/tinc/A/hosts/D.pub
-D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+D stores a copy of C's public key in /etc/tinc/hosts/C.pub
@subsubheading Starting
-A has to start their tincd first. Then come B and C, where C has to
+A has to start their tincd first. Then come B and C, where C has to
provide the option `-n A', because they have more than one tinc
-network. Finally, D's tincd is started.
+network. Finally, D's tincd is started.
@chapter Running tinc
Running tinc isn't just as easy as typing `tincd' and hoping everything
-will just work out the way you wanted. Instead, the use of tinc is a
+will just work out the way you wanted. Instead, the use of tinc is a
project that involves trust relations and more than one computer.
@menu
* Managing keys::
* Runtime options::
+* Error messages::
@end menu
@node Managing keys, Runtime options, Running tinc, Running tinc
@section Managing keys
-Before attempting to start tinc, you have to create passphrases. When
-tinc tries to make a connection, it exchanges some sensitive
-data. Before doing so, it likes to know if the other end is
+Before attempting to start tinc, you have to create public/private keypairs.
+When tinc tries to make a connection, it exchanges some sensitive
+data. Before doing so, it likes to know if the other end is
trustworthy.
-To do this, both ends must have some knowledge about the other. In the
-case of tinc this is the authentication passphrase.
+To do this, both ends must have some knowledge about the other. In the
+case of tinc this is the public keys.
-This passphrase is a number, which is chosen at random. This number is
-then sent to the other computers which want to talk to us directly. To
-avoid breaking security, this should be done over a known secure channel
-(such as ssh or similar).
+To generate a public/private keypair, run `tincd -n vpn-name -K<bits>'.
+<bits> is optional, you can use it to specify the length of the keys.
+The length of the public/private keypairs
+should be at least 1024 for reasonable security (reasonable being good enough
+to keep the NSA busy for a few weeks).
-All passphrases are stored in the passphrases directory, which is
-normally /etc/tinc/nn/passphrases/, but it may be changed using the
-`Passphrases' option in the config file.
+Every computer that wants to participate in the VPN should do this. The
+public keyfile should get the name of each tinc daemon and an extension .pub,
+and it should be stored in the hosts directory.
-To generate a passphrase, run `genauth'. genauth takes one argument,
-which is the length of the passphrase in bits. The length of the
-passphrase should be in the range 1024--2048 for a key length of 128
-bits. genauth creates a random number of the specified length, and puts
-it to stdout.
-
-Every computer that wants to participate in the VPN should do this, and
-store the output in the passphrases directory, in the file @file{local}.
-
-When every computer has his own local key, it should copy it to the
-computer that it wants to talk to directly. (i.e. the one it connects to
-during startup.) This should be done via a secure channel, because it is
-sensitive information. If this is not done securely, someone might break
-in on you later on.
-
-Those non-local passphrase files must have the name of the VPN IP
-address that they will advertise to you. For instance, if a computer
-tells us it likes to be 10.1.1.3 with netmask 255.255.0.0, the file
-should still be called 10.1.1.3, and not 10.1.0.0.
+When every computer has his own keys and configuration files, the files in the
+hosts directory should be exchanged with each other computer that it wants to
+talk to directly. Since only public keys are involved, you can safely do this
+via email, telnet or ftp, or even putting the contents on a public billboard.
@c ==================================================================
-@node Runtime options, , Managing keys, Running tinc
+@node Runtime options, Error messages, Managing keys, Running tinc
@section Runtime options
Besides the settings in the configuration file, tinc also accepts some
command line options.
-This list is a longer version of that in the manpage. The latter is
+This list is a longer version of that in the manpage. The latter is
generated automatically, so may be more up-to-date.
+@cindex command line
+@cindex runtime options
+@cindex options
@c from the manpage
-@table @asis
-@item -c, --config=FILE
-Read configuration options from FILE. The default is
-@file{/etc/tinc/nn/tinc.conf}.
+@table @samp
+@item -c, --config=PATH
+Read configuration options from the directory PATH. The default is
+@file{/etc/tinc/nn/}.
@item -d
-Increase debug level. The higher it gets, the more gets
-logged. Everything goes via syslog.
+Increase debug level. The higher it gets, the more gets
+logged. Everything goes via syslog.
0 is the default, only some basic information connection attempts get
-logged. Setting it to 1 will log a bit more, still not very
-disturbing. With two -d's tincd will log protocol information, which can
-get pretty noisy. Three or more -d's will output every single packet
+logged. Setting it to 1 will log a bit more, still not very
+disturbing. With two -d's tincd will log protocol information, which can
+get pretty noisy. Three or more -d's will output every single packet
that goes out or comes in, which probably generates more data than the
packets themselves.
@item -k, --kill
-Attempt to kill a running tincd and exit. A TERM signal (15) gets sent
-to the daemon that his its PID in /var/run/tinc.nn.pid.
+Attempt to kill a running tincd and exit. A TERM signal (15) gets sent
+to the daemon that his its PID in /var/run/tinc.pid.
-Because it kills only one tincd, you should use -n here if you use it
-normally.
+Because it kills only one tinc daemon, you should use -n here if you
+started it that way. It will then read the PID from
+@file{/var/run/tinc.NETNAME.pid}.
@item -n, --net=NETNAME
-Connect to net NETNAME. @xref{Multiple networks}.
+Connect to net NETNAME. @xref{Multiple networks}.
-@item -t, --timeout=TIMEOUT
-Seconds to wait before giving a timeout. Should not be set too low,
-because every time tincd senses a timeout, it disconnects and reconnects
-again, which will cause unnecessary network traffic and log messages.
+@item -K, --generate-keys[=BITS]
+Generate public/private keypair of BITS length. If BITS is not specified,
+1024 is the default. tinc will ask where you want to store the files,
+but will default to the configuration directory (you can use the -c or -n option
+in combination with -K). After that, tinc will quit.
@item --help
Display a short reminder of these runtime options and terminate.
@end table
+@c ==================================================================
+@node Error messages, , Runtime options, Running tinc
+@section Error messages
+
+What follows is a list of the most common error messages you can see
+when configuring tinc. Most of these messages are visible in the syslog
+only, so keep an eye on it!
+
+@table @strong
+@item Could not open /dev/tap0: No such device
+@table @bullet
+@item You forgot to insmod netlink_dev.o
+@item You forgot to compile `Netlink device emulation' in the kernel
+@end table
+
+@item Can't write to tun/tap device: No such device
+@table @bullet
+@item You forgot to insmod tun.o
+@item You forgot to compile `Universal TUN/TAP driver' in the kernel
+@end table
+
+@item Packet with destination 1.2.3.4 is looping back to us!
+@table @bullet
+@item Something is not configured right. Packets are being sent out to the
+tap device, but according to the Subnet directives in your host configuration
+file, those packets should go to your own host. Most common mistake is that
+you have a Subnet line in your host configuration file with a netmask which is
+just as large as the netmask of the tap device. The latter should in almost all
+cases be larger. Rethink your configuration.
+Note that you will only see this message if you specified a debug
+level of 5 or higher!
+@end table
+
+@item Network address and subnet mask do not match!
+@table @bullet
+@item The Subnet field must contain a network address
+If you only want to use one IP address, set the netmask to /32.
+@end table
+
+@item This is a bug: net.c:253: 24: Some error
+@table @bullet
+@item This is something that should not have happened
+Please report this, and tell us exactly what went wrong before you got
+this message. In normal operation, these errors should not occur.
+@end table
+
+@item Error reading RSA key file `rsa_key.priv': No such file or directory
+@table @bullet
+@item You must specify the complete pathname
+Specifying a relative path does not make sense here. tinc changes its
+directory to / when starting (to avoid keeping a mount point busy); and
+even if we built in a default directory to look for these files, the key
+files are bound to be in a different directory.
+@end table
+
+@end table
+
+@end table
+
@c ==================================================================
@node Technical information, About us, Running tinc, Top
@chapter Technical information
-@c ==================================================================
@menu
* The Connection::
* Security::
@end menu
+
+@c ==================================================================
@node The Connection, Security, Technical information, Technical information
@section The basic philosophy of the way tinc works
-@cindex Connection
+@cindex connection
tinc is a daemon that takes VPN data and transmit that to another host
computer over the existing Internet infrastructure.
@cindex ethertap
@cindex frame type
The data itself is read from a character device file, the so-called
-@emph{ethertap} device. This device is associated with a network
-interface. Any data sent to this interface can be read from the device,
-and any data written to the device gets sent from the interface. Data to
+@emph{ethertap} device. This device is associated with a network
+interface. Any data sent to this interface can be read from the device,
+and any data written to the device gets sent from the interface. Data to
and from the device is formatted as if it were a normal ethernet card,
so a frame is preceded by two MAC addresses and a @emph{frame type}
field.
So when tinc reads an ethernet frame from the device, it determines its
-type. Right now, tinc can only handle Internet Protocol version 4 (IPv4)
-frames. Plans to support other protocols are being made. When tinc knows
+type. Right now, tinc can only handle Internet Protocol version 4 (IPv4)
+frames, because it needs IP headers for routing.
+Plans to support other protocols and switching instead of routing are being made.
+When tinc knows
which type of frame it has read, it can also read the source and
destination address from it.
-Now it is time that the frame gets encrypted. Currently the only
+Now it is time that the frame gets encrypted. Currently the only
encryption algorithm available is blowfish.
@cindex encapsulating
When the encryption is ready, time has come to actually transport the
-packet to the destination computer. We do this by sending the packet
-over an UDP connection to the destination host. This is called
+packet to the destination computer. We do this by sending the packet
+over an UDP connection to the destination host. This is called
@emph{encapsulating}, the VPN packet (though now encrypted) is
encapsulated in another IP datagram.
When the destination receives this packet, the same thing happens, only
-in reverse. So it does a decrypt on the contents of the UDP datagram,
+in reverse. So it does a decrypt on the contents of the UDP datagram,
and it writes the decrypted information to its own ethertap device.
+To let the kernel on the receiving end accept the packet, the destination MAC
+address must match that of the tap interface. Because of the routing nature
+of tinc, ARP is not possible. tinc solves this by always overwriting the
+destination MAC address with fe:fd:0:0:0:0. That is also the reason why you must
+set the MAC address of your tap interface to that address.
+
@c ==================================================================
@node The Meta-connection, , Protocol Preview, The Connection
@subsection The meta-connection
-Having only an UDP connection available is not enough. Though suitable
+Having only an UDP connection available is not enough. Though suitable
for transmitting data, we want to be able to reliably send other
information, such as routing and encryption information to somebody.
TCP is a better alternative, because it already contains protection
against information being lost, unlike UDP.
-So we establish two connections. One for the encrypted VPN data, and one
-for other information, the meta-data. Hence, we call the second
-connection the meta-connection. We can now be sure that the
+So we establish two connections. One for the encrypted VPN data, and one
+for other information, the meta-data. Hence, we call the second
+connection the meta-connection. We can now be sure that the
meta-information doesn't get lost on the way to another computer.
@cindex data-protocol
@cindex meta-protocol
Like with any communication, we must have a protocol, so that everybody
-knows what everything stands for, an how he should react. Because we
-have two connections, we also have two protocols. The protocol used for
+knows what everything stands for, and how she should react. Because we
+have two connections, we also have two protocols. The protocol used for
the UDP data is the ``data-protocol,'' the other one is the
``meta-protocol.''
The reason we don't use TCP for both protocols is that UDP is much
-better for encapsulation, even while it is less reliable. The real
+better for encapsulation, even while it is less reliable. The real
problem is that when TCP would be used to encapsulate a TCP stream
that's on the private network, for every packet sent there would be
-three ACK's sent instead of just one. Furthermore, if there would be
+three ACK's sent instead of just one. Furthermore, if there would be
a timeout, both TCP streams would sense the timeout, and both would
start resending packets.
@cindex Cabal
tinc got its name from ``TINC,'' short for @emph{There Is No Cabal}; the
alleged Cabal was/is an organization that was said to keep an eye on the
-entire Internet. As this is exactly what you @emph{don't} want, we named
+entire Internet. As this is exactly what you @emph{don't} want, we named
the tinc project after TINC.
@cindex SVPN
But in order to be ``immune'' to eavesdropping, you'll have to encrypt
-your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
+your data. Because tinc is a @emph{Secure} VPN (SVPN) daemon, it does
exactly that: encrypt.
This chapter is a mixture of ideas, reasoning and explanation, please
@menu
* Key Types::
-* Key Management::
-* Authentication::
-* Protection::
@end menu
@c ==================================================================
-@node Key Types, Key Management, Security, Security
+@node Key Types, , Security, Security
@subsection Key Types
@c FIXME: check if I'm not talking nonsense
-There are several types of encryption keys. Tinc uses two of them,
+There are several types of encryption keys. Tinc uses two of them,
symmetric private keypairs and public/private keypairs.
-Public/private keypairs are used in public key cryptography. It enables
+Public/private keypairs are used in public key cryptography. It enables
someone to send out a public key with which other people can encrypt their
-data. The encrypted data now can only be decrypted by the person who has
-the private key that matches the public key. So, a public key only allows
-@emph{other} people to send encrypted messages to you. This is very useful
-in setting up private communications channels. Just send out your public key
-and other people can talk to you in a secure way. But how can you know
-the other person is who he says he is?
-
-For authentication itself tinc uses symmetric private keypairs, referred
-to as a passphrase. The identity of each tinc daemon is defined by it's
-passphrase (like you can be identified by your social security number).
-Every tinc daemon that is allowed to connect to you has a copy of your
-passphrase (hence symmetrical).
-
-It would also be possible to use public/private keypairs for authentication,
-so that you could shout out your public key and don't need to keep it
-secret (like the passphrase you would have to send to someone else). Also,
-no one else has to know a private key from you.
-Both forms have their pros and cons, and at the moment tinc just uses passphrases
-(which are computationaly more efficient and perhaps in some way more
-secure).
+data. The encrypted data now can only be decrypted by the person who has
+the private key that matches the public key. So, a public key only allows
+@emph{other} people to send encrypted messages to you. This is very useful
+in setting up private communications channels. Just send out your public key
+and other people can talk to you in a secure way. But how can you know
+the other person is who she says she is? This is done by sending out an
+encrypted challenge that only the person with the right private key can decode
+an respond to.
-@c ==================================================================
-@node Key Management, Authentication, Key Types, Security
-@subsection Key Management
-@c FIXME change for the current protocol
-
-@cindex Diffie-Hellman
-You can't just send a private encryption key to your peer, because
-somebody else might already be listening to you. So you'll have to
-negotiate over a shared but secret key. One way to do this is by using
-the ``Diffie-Hellman key exchange'' protocol
-(@uref{http://www.rsa.com/rsalabs/faq/html/3-6-1.html}). The idea is as
-follows.
-
-You have two participants A and B that want to agree over a shared
-secret encryption key. Both parties have some large prime number p and a
-generator g. These numbers may be known to the outside world, and hence
-may be included in the source distribution.
-
-@cindex secret key
-Both parties then generate a secret key. A generates a, and computes g^a
-mod p. This is then sent to B; while B computes g^b mod p, and transmits
-this to A, b being generated by B. Both a and b must be smaller than
-p-1.
+However, encryption with public/private keys is very slow. Symmetric key cryptography
+is orders of magnitudes faster, but it is very hard to safely exchange the symmetric
+keys, since they should be kept private.
-Both parties then calculate g^ab mod p = k. k is the new, shared, but
-still secret key.
-
-To obtain a key k of a sufficient length (128 bits in our vpnd), p
-should be 2^129-1 or more.
+The idea is to use public/private cryptography for authentication, and for
+exchanging symmetric keys in a safe way. After that, all communications are encrypted
+with the symmetric cipher.
-@c ==================================================================
-@node Authentication, Protection, Key Management, Security
-@subsection Authentication
-@c FIXME: recheck
-
-@cindex man-in-the-middle attack
-Because the Diffie-Hellman protocol is in itself vulnerable to the
-``man-in-the-middle attack,'' we should introduce an authentication
-system.
-
-We will let A transmit a passphrase that is also known to B encrypted
-with g^a, before A sends this to B. This way, B can check whether A is
-really A or just someone else.
-B will never receive the real passphrase though, because it was
-encrypted using public/private keypairs. This way there is no way an
-imposter could steal A's passphrase.
-
-@cindex passphrase
-@c ehrmz... but we only use 1024 bits passphrases ourselves? [guus]
-This passphrase should be 2304 bits for a symmetric encryption
-system. But since an asymmetric system is more secure, we could do with
-2048 bits. This only holds if the passphrase is very random.
-
-These passphrases could be stored in a file that is non-readable by
-anyone else but root; e.g. @file{/etc/tinc/passphrases} with UID 0
-and permissions mode 700.
-
-The only thing that needs to be taken care of is how A can securely send
-a copy of it's passphrase to B if B doesn't have it yet. This could be
-done via mail with PGP, but you should be really convinced of the
-identity of the person who owns the email address you are sending this to.
-Swapping floppy disks in real life might be the best way to do this!
-
-
-@c ==================================================================
-@node Protection, , Authentication, Security
-@subsection Protecting your data
-
-Now we have securely hidden our data. But a malicious cracker may still
-bother you by randomly altering the encrypted data he intercepts.
-
-@c FIXME what the hell is this all about? remove? IT
-
@c ==================================================================
@node About us, Concept Index, Technical information, Top
@chapter About us
tinc's main page is at @url{http://tinc.nl.linux.org/},
this server is located in the Netherlands.
-We have an IRC channel on the Open Projects IRC network. Connect to
+We have an IRC channel on the Open Projects IRC network. Connect to
@uref{http://openprojects.nu/services/irc.html, irc.openprojects.net},
and join channel #tinc.
@item Ivo Timmermans (zarq) (@email{itimmermans@@bigfoot.com})
Main coder/hacker and maintainer of the package.
-@item Guus Sliepen (guus)
+@item Guus Sliepen (guus) (@email{guus@@sliepen.warande.net})
Originator of it all, co-author.
-@item Wessel Dankers (Ubiq)
-General obfuscater of the code.
+@item Wessel Dankers (Ubiq) (@email{wsl@@nl.linux.org})
+For the name `tinc' and various suggestions.
@end table
-Thank you's to: Dekan, Emphyrio, vDong
-
-Greetings to: braque, Fluor, giggles, macro, smoke, tribbel
+We have received a lot of valuable input from users. With their help,
+tinc has become the flexible and robust tool that it is today. We have
+composed a list of contributions, in the file called @file{THANKS} in
+the source distribution.
@c ==================================================================
projects / tinc / blobdiff