\input texinfo @c -*-texinfo-*-
-@c $Id: tinc.texi,v 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+@c $Id: tinc.texi,v 1.8.4.15 2001/05/19 15:50:51 guus 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 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+$Id: tinc.texi,v 1.8.4.15 2001/05/19 15:50:51 guus 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 1.8.4.10 2000/12/05 08:54:22 zarq Exp $
+$Id: tinc.texi,v 1.8.4.15 2001/05/19 15:50:51 guus Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
@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
+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
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
+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.
@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:
+The official release only truly supports Linux.
+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.
+tinc uses the ethertap device or the universal TUN/TAP driver. The former is provided in the standard kernel
+from version 2.1.60 up to 2.3.x, but has been replaced in favour of the TUN/TAP driver in kernel versions 2.4.0 and later.
@c ==================================================================
@subsection FreeBSD
tinc on FreeBSD relies on the universial TUN/TAP driver for its data
-acquisition from the kernel. Therefore, tinc suports the same platforms
+acquisition from the kernel. Therefore, tinc works on the same platforms
as this driver. These are: FreeBSD 3.x, 4.x, 5.x.
@subsection Solaris
tinc on Solaris relies on the universial TUN/TAP driver for its data
-acquisition from the kernel. Therefore, tinc suports the same platforms
+acquisition from the kernel. Therefore, tinc works on the same platforms
as this driver. These are: Solaris, 2.1.x.
@node Configuring the kernel, Libraries, Installing tinc - preparations, Installing tinc - preparations
@section Configuring the kernel
-If you are running Linux, chances are good that your kernel already
-supports all the devices that tinc needs for proper operation. For
-example, the standard kernel from Redhat Linux already has support for
-ethertap and netlink compiled in. Debian users can use the modconf
-utility to select the modules. If your Linux distribution supports this
-method of selecting devices, look out for something called `ethertap',
-and `netlink_dev'. You need both these devices.
+If you are running Linux, chances are good that your kernel already supports
+all the devices that tinc needs for proper operation. For example, the
+standard kernel from Redhat Linux already has support for ethertap and netlink
+compiled in. Debian users can use the modconf utility to select the modules.
+If your Linux distribution supports this method of selecting devices, look out
+for something called `ethertap', and `netlink_dev' if it is using a kernel
+version prior to 2.4.0. In that case you will need both these devices. If you
+are using kernel 2.4.0 or later, you need to select `tun'.
If you can install these devices in a similar manner, you may skip this
section.
@node Configuration of the Linux kernel, Configuration of the FreeBSD kernel, Configuring the kernel, Configuring the kernel
@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
-is not really possible, unless someone tells me someone ported the
-ethertap and netlink devices back to 2.0.
+First of all, a kernel version of 2.1.60 or higher is @emph{required}.
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!
-Here are the options you have to turn on when configuring a new
-kernel.
+Here are the options you have to turn on when configuring a new kernel.
-For kernel 2.2.x:
+For kernels 2.1.60 up to 2.4.0:
@example
Code maturity level options
[*] Prompt for development and/or incomplete code/drivers
Networking options
[*] Kernel/User netlink socket
-<*> Netlink device emulation
+<M> Netlink device emulation
Network device support
-<*> Ethertap network tap
+<M> Ethertap network tap
@end example
-For kernel 2.3.x and 2.4.x:
+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, otherwise
+you can also choose to compile it directly into the kernel.
+
+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}:
+
+@example
+alias char-major-36 netlink_dev
+alias tap0 ethertap
+options tap0 -o tap0 unit=0
+alias tap1 ethertap
+options tap1 -o tap1 unit=1
+@end example
+
+Add more alias/options lines if necessary.
+
+For kernels 2.4.0 and higher:
@example
Code maturity level options
[*] Prompt for development and/or incomplete code/drivers
-Networking options
-[*] Kernel/User netlink socket
-<*> Netlink device emulation
Network device support
-<*> Universal TUN/TAP device driver support
+<M> Universal TUN/TAP device driver support
@end example
+It's not necessary to compile this driver as a module, even if you are going to
+run more than one instance of tinc.
-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}.
+If you have an early 2.4 kernel, you can choose both the TUN/TAP driver and the
+`Ethertap network tap' device. This latter is marked obsolete, and chances are
+that it won't even function correctly anymore. Make sure you select the
+universal TUN/TAP driver.
+
+If you decide to build the TUN/TAP driver as a kernel module, add these lines
+to @file{/etc/modules.conf}:
@example
-alias tap0 ethertap
-alias char-major-36 netlink_dev
+alias char-major-10-200 tun
@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.
-
-Finally, after having set up other options, build the kernel and boot
-it. Unfortunately it's not possible to insert these modules in a
-running kernel.
-
@c ==================================================================
@node Configuration of the FreeBSD kernel, Configuration of the Solaris kernel, Configuration of the Linux kernel, Configuring the kernel
@cindex OpenSSL
For all cryptography-related functions, tinc uses the functions provided
-by the OpenSSL library. We recommend using version 0.9.5 or 0.9.6 of
-this library. Other versions may also work, but we can guarantee
-nothing.
+by the OpenSSL library.
If this library is not installed, you wil get an error when configuring
tinc for build. Support for running tinc without having OpenSSL
eavesdropping would become a bit too easy. This does, however, imply
that you'd have to run tincd as root.
-If you use the universal TUN/TAP driver, you have to create the
-following device files (unless they already exist):
+If you use Linux and have a kernel version prior to 2.4.0, you have to make the
+ethertap devices:
@example
-mknod -m 600 /dev/... c .. ..
-chown 0.0 /dev/...
+mknod -m 600 /dev/tap0 c 36 16
+chown 0.0 /dev/tap0
@end example
-If you want to have more devices, the device numbers will be .. .. ...
-
-If you use Linux, and you run the new 2.4 kernel using the devfs
-filesystem, then the tap device will be automatically generated as
-@file{/dev/netlink/tap0}.
+Any further ethertap devices have minor device number 16 through 31.
-If you use Linux and have kernel 2.2.x, you have to make the ethertap
-devices:
+If you use the universal TUN/TAP driver, you have to create the
+following device files (unless they already exist):
@example
-mknod -m 600 /dev/tap0 c 36 16
-chown 0.0 /dev/tap0
+mknod -m 600 /dev/tun c 10 200
+chown 0.0 /dev/tun
@end example
-Any further ethertap devices have minor device number 16 through 31.
+If you use Linux, and you run the new 2.4 kernel using the devfs filesystem,
+then the TUN/TAP device will probably be automatically generated as
+@file{/dev/net/tun}.
@c ==================================================================
myvpn 10.0.0.0
@end example
-This has nothing to do with the MyVPNIP configuration variable that will be
-discussed later, it is only to make the output of the route command more
-legible.
-
@subsubheading @file{/etc/services}
You may add this line to @file{/etc/services}. The effect is that you
@node Interfaces, , System files, Installing tinc - installation
@section Interfaces
-Before you can start transmitting data over the tinc tunnel, you must
+Before you can start transmitting data over the tinc tunnel, tinc must
set up the ethertap network devices.
First, decide which IP addresses you want to have associated with these
numbers when you are going to configure tinc itself. @xref{Configuring
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
-to start a tincd.
+tinc will open an ethertap device or TUN/TAP device, which will also
+create a network interface called `tap0', `tap1' etc. if you are using
+the ethertap driver, or a network interface with the same name as NETNAME
+if you are using the universal TUN/TAP driver.
+
+You can configure that device by putting ordinary ifconfig, route, and other commands
+to a script named @file{/etc/tinc/NETNAME/tinc-up}. When tinc starts, this script
+will be executed. When tinc exits, it will execute the script named
+@file{/etc/tinc/NETNAME/tinc-down}, but normally you don't need to create that script.
-The actual setup of the ethertap device is quite simple, just repeat
-after me:
+An example @file{tinc-up} script when using the TUN/TAP driver:
@example
-ifconfig tap@emph{n} hw ether fe:fd:00:00:00:00
+ifconfig $NETNAME hw ether fe:fd:00:00:00:00
+ifconfig $NETNAME @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
+ifconfig $NETNAME -arp
@end example
@cindex MAC address
@cindex hardware address
-@strong{Note:} Since version 1.0pre3, all interface addresses are set to
-this address, whereas previous versions required the MAC to match the
-actual IP address.
+The first line sets up the MAC address of the network interface.
+Due to the nature of how ethernet and tinc work, it has to be set to fe:fd:00:00:00:00.
+(tinc versions prior to 1.0pre3 required that the MAC address matched the IP address.)
+You can use the environment variable $NETNAME to get the name of the interface.
+If you are using the ethertap driver however, you need to replace it with tap@emph{n},
+corresponding to the device file name.
@cindex ifconfig
-To activate the device, you have to assign an IP address to it. To set
-an IP address @emph{IP} with network mask @emph{mask}, do the following:
-
-@example
-ifconfig tap@emph{n} @emph{xx}.@emph{xx}.@emph{xx}.@emph{xx} netmask @emph{mask}
-@end example
-
+The next line gives the interface an IP address and a netmask.
+The kernel will also automatically add a route to this interface, so normally you don't need
+to add route commands to the @file{tinc-up} script.
+The kernel will also bring the interface up after this command.
@cindex netmask
The netmask is the mask of the @emph{entire} VPN network, not just your
-own subnet. It is the same netmask you will have to specify with the
-VpnMask configuration variable.
+own subnet.
+
+@cindex arp
+The last line tells the kernel not to use ARP on that interface.
+Again this has to do with how ethernet and tinc work. Don't forget to add this line.
@c
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 make it even harder for crackers, even though it is thought
-to be nearly impossible to crack a single key.
+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
+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
+use this number as the argument for his ConnectPort.
@item @strong{Name = <name>}
This is a symbolic name for this connection. It can be anything
same amount of seconds, the connection is terminated, and the others
will be notified of this.
-@item @strong{PrivateKey = <path>}
+@item PrivateKey = <key> (obsolete)
+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 @strong{PrivateKeyFile = <path>} (recommended)
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. (NOTE: In version 1.0pre3, this variable was used
-to give the key inline. This is no longer supported.)
+relative directory.
-@item TapDevice = <device> (/dev/tap0)
+@item @strong{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
about configuring an ethertap device for Linux.
-@item VpnMask = <mask>
-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.
+@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
+who want to run a tinc daemon from behind a masquerading firewall, or if
+UDP packet routing is disabled somehow. This is experimental code,
+try this at your own risk.
@end table
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)
+@item IndirectData = <yes|no> (no, experimental)
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
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 = <path>
+@item PublicKey = <key> (obsolete)
+This is the RSA public key for this host.
+
+@item PublicKeyFile = <path> (obsolete)
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.)
+directory.
+
+From version 1.0pre4 on tinc will store the public key directly into the
+host configuration file in PEM format, the above two options then are not
+necessary. Either the PEM format is used, or 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. 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'.
+the host that defines it.
-The range must contain the IP address of the tap device, not the real IP
-address of the host running tincd.
+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.
+/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)
+@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 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.}
+firewall, or if UDP packet routing is disabled somehow. This is
+experimental code, try this at your own risk. It may not work at all.
@end table
be anything, as long as all these names are unique across the entire
VPN.
-@item PrivateKey
+@item PrivateKeyFile
Fill in the full pathname to the file that contains the private RSA key.
@item ConnectTo
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:
+`@emph{host configuration file}', the public key must be present
+and 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.
+Actually it is not stricly required, but you need it to send packets to
+other tinc daemons.
@end table
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.
+configuration file.
-For each host configuration file, you add two variables:
+If it is not already present, make sure you add this variable:
@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.
@cindex example
-Imagine the following situation. An A-based company wants to connect
+Imagine the following situation. Branch A of our example `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.
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.
+how these example host is set up. All branches use the netname `company'
+for this particular VPN.
-@subsubheading For A
+@subsubheading For Branch A
-@emph{A} would be configured like this:
+@emph{BranchA} would be configured like this:
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
+# Real interface of internal network:
+# ifconfig eth0 10.1.54.1 netmask 255.255.0.0 broadcast 10.1.255.255
+
ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.1.54.1 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = A
-PrivateKey = /etc/tinc/A.priv
-VpnMask = 255.0.0.0
+Name = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
+TapDevice = /dev/tap0
@end example
-On all hosts, /etc/tinc/hosts/A contains:
+On all hosts, /etc/tinc/company/hosts/BranchA contains:
@example
Subnet = 10.1.0.0/16
Address = 1.2.3.4
-PublicKey = /etc/tinc/hosts/A.pub
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For B
+@subsubheading For Branch B
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
+# Real interface of internal network:
+# ifconfig eth0 10.2.43.8 netmask 255.255.0.0 broadcast 10.2.255.255
+
ifconfig tap0 hw ether fe:fd:00:00:00:00
ifconfig tap0 10.2.1.12 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = B
-ConnectTo = A
-PrivateKey = /etc/tinc/B.priv
-VpnMask = 255.0.0.0
+Name = BranchB
+ConnectTo = BranchA
+PrivateKey = /etc/tinc/company/rsa_key.priv
@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
connect to this node.
-On all hosts, /etc/tinc/hosts/B:
+On all hosts, in @file{/etc/tinc/company/hosts/BranchB}:
@example
Subnet = 10.2.0.0/16
Address = 2.3.4.5
-PublicKey = /etc/tinc/hosts/B.pub
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For C
+@subsubheading For Branch C
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
-ifconfig tap0 hw ether fe:fd:00:00:00:00
-ifconfig tap0 10.3.69.254 netmask 255.0.0.0
+# Real interface of internal network:
+# ifconfig eth0 10.3.69.254 netmask 255.255.0.0 broadcast 10.3.255.255
+
+ifconfig tap1 hw ether fe:fd:00:00:00:00
+ifconfig tap1 10.3.69.254 netmask 255.0.0.0
+ifconfig tap1 -arp
@end example
-and in /etc/tinc/A/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-Name = C
-ConnectTo = A
+Name = BranchC
+ConnectTo = BranchA
TapDevice = /dev/tap1
-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 knows the portnumber it has to listen on
+from it's own host configuration file.
-On all hosts, /etc/tinc/hosts/C:
+On all hosts, in @file{/etc/tinc/company/hosts/BranchC}:
@example
+Address = 3.4.5.6
Subnet = 10.3.0.0/16
Port = 2000
-PublicKey = /etc/tinc/hosts/C.pub
+
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
@end example
-@subsubheading For D
+@subsubheading For Branch D
+
+In @file{/etc/tinc/company/tinc-up}:
@example
-#ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
+# Real interface of internal network:
+# ifconfig tap0 10.4.3.32 netmask 255.255.0.0 broadcast 10.4.255.255
+
ifconfig tap0 hw ether fe:fd:0a:04:03:20
ifconfig tap0 10.4.3.32 netmask 255.0.0.0
+ifconfig tap0 -arp
@end example
-and in /etc/tinc/tinc.conf:
+and in @file{/etc/tinc/company/tinc.conf}:
@example
-MyVirtualIP = 10.4.3.32/16
-ConnectTo = 3.4.5.6
-ConnectPort = 2000
-VpnMask=255.0.0.0
+Name = BranchD
+ConnectTo = BranchC
+PrivateKeyFile = /etc/tinc/company/rsa_key.priv
@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
-to have a different ListenPort.
+port 2000. It knows the port number from the host configuration file.
-@subsubheading Key files
+On all hosts, in @file{/etc/tinc/company/hosts/BranchD}:
-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 stores a copy of B's passphrase in /etc/tinc/passphrases/10.2.1.12
+@example
+Subnet = 10.4.0.0/16
+Address = 4.5.6.7
-A stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+-----BEGIN RSA PUBLIC KEY-----
+...
+-----END RSA PUBLIC KEY-----
+@end example
-B stores a copy of A's passphrase in /etc/tinc/passphrases/10.1.54.1
+@subsubheading Key files
-C stores a copy of A's passphrase in /etc/tinc/A/passphrases/10.1.54.1
+A, B, C and D all have generated a public/private keypair with the following command:
-C stores a copy of D's passphrase in /etc/tinc/A/passphrases/10.4.3.32
+@example
+tincd -n company -K
+@end example
-D stores a copy of C's passphrase in /etc/tinc/passphrases/10.3.69.254
+The private key is stored in @file{/etc/tinc/company/rsa_key.priv},
+the public key is put into the host configuration file in the @file{/etc/tinc/company/hosts/} directory.
+During key generation, tinc automatically guesses the right filenames based on the -n option and
+the Name directive in the @file{tinc.conf} file (if it is available).
@subsubheading Starting
-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.
-
+After each branch has finished configuration and they have distributed
+the host configuration files amongst them, they can start their tinc daemons.
+They don't necessarily have to wait for the other branches to have started
+their daemons, tinc will try connecting until they are available.
@c ==================================================================
@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
+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.
+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 ==================================================================
@cindex options
@c from the manpage
@table @samp
-@item -c, --config=FILE
-Read configuration options from FILE. The default is
-@file{/etc/tinc/nn/tinc.conf}.
+@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
@item -n, --net=NETNAME
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.
@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 insmod netlink_dev.o or ethertap.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
+@item Can't write to /dev/net/tun: No such device
@table @bullet
@item You forgot to insmod tun.o
@item You forgot to compile `Universal TUN/TAP driver' in the kernel
@item Packet with destination 1.2.3.4 is looping back to us!
@table @bullet
-@item Some host has an IP address range that overlaps with yours
-Different hosts must have different IP ranges (as given with Subnet in
-the host configuration files). tinc relies on this information to route
-its data, so each IP address range must have exactly one host
-associated. You will only see this message if you specified a debug
+@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
files are bound to be in a different directory.
@end table
-@item Error reading RSA key file `fd47...8ceb': No such file or directory
-@table @bullet
-@item You specified the key here, not a pathname
-In version 1.0pre3, you had to put your key here. This has changed, the
-keys are now stored in separate files. This means you have to
-regenerate these keys.
-@end table
-
@end table
-
-
@c ==================================================================
@node Technical information, About us, Running tinc, Top
@chapter Technical information
+
@menu
* The Connection::
* Security::
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
+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.
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
@menu
* Key Types::
-* Key Management::
-* Authentication::
@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
@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?
-
-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).
-
-@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.
+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.
-@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.
-
-
-@c ==================================================================
-@node Authentication, , 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!
+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 ==================================================================
@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
projects / tinc / blobdiff