Getting at a machine behind a ISDN router
Carlos Sousa
csousa at tvtel.pt
Thu Oct 17 00:52:47 CEST 2002
On Sun, 13 Oct 2002 11:19:18 +0200 Guus Sliepen <guus at sliepen.eu.org> wrote:
> On Sat, Oct 12, 2002 at 11:43:49PM +0100, Carlos Sousa wrote:
>
> > Pinging the client machine (10.0.2.1) from the server machine (10.0.1.1)
> > and running iptraf on the server shows traffic between the 2 machines,
> > both ways, but the packets are still lost. I smell a routing problem
> > concerning the echo-reply packets that are arriving at server, but I can't
> > see where.
There is definitely traffic between the 2 machines, I can see that in
/var/log/syslog on both machines. The tincs appear to be getting along fine,
but I still can't access anything through the vpn.
The weird thing happened again on Monday: sitting at "miragaia", I opened
a ssh connection to "vbc", and tested the vpn. It worked! I could ping and
otherwise access everything on both machines. I checked a few hours later
and the vpn didn't work again, and I couldn't get it going ever since.
> Could you show us the full "route -n" and "ifconfig -a" output and
> tinc.conf for both vbc and miragaia? Also, the output of "iptables -L -v
> -x -n" if there's a firewall on either host.
----------------------------------------------------------------------
miragaia: (no public access, the one that initiates the connection)
$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
224.0.0.0 0.0.0.0 240.0.0.0 U 0 0 0 eth0
0.0.0.0 192.168.4.9 0.0.0.0 UG 0 0 0 eth1
(No entry for the vpn!?)
$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:06:5B:64:12:7A
inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:144301 errors:0 dropped:0 overruns:1 frame:0
TX packets:238487 errors:0 dropped:0 overruns:0 carrier:0
collisions:17541 txqueuelen:100
RX bytes:14280131 (13.6 MiB) TX bytes:284690066 (271.5 MiB)
Interrupt:18 Base address:0xd480
eth1 Link encap:Ethernet HWaddr 00:E0:7D:77:53:1A
inet addr:192.168.4.1 Bcast:192.168.4.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1199 errors:0 dropped:0 overruns:0 frame:0
TX packets:1114 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:855834 (835.7 KiB) TX bytes:95276 (93.0 KiB)
Interrupt:16 Base address:0xec00
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:35792 errors:0 dropped:0 overruns:0 frame:0
TX packets:35792 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:14741939 (14.0 MiB) TX bytes:14741939 (14.0 MiB)
vbcnet Link encap:Ethernet HWaddr 00:FF:C9:A8:27:83
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:5 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:490 (490.0 b) TX bytes:0 (0.0 b)
(The HWaddr is wrong, should be FE:FD:00:00:00:00)
Contents of tinc-up:
#!/bin/sh
ifconfig $INTERFACE hw ether fe:fd:0:0:0:0
ifconfig $INTERFACE 10.0.2.1 netmask 255.255.0.0
ifconfig $INTERFACE -arp
(why isn't this working?)
The firewall is completely open, the *real* firewall is either at the
router or on the school's ISP premises, so I can't touch it.
----------------------------------------------------------------------
vbc: (public ip, connected to by "miragaia")
$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
195.23.75.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.0.0.0 0.0.0.0 255.255.0.0 U 0 0 0 vbcnet
224.0.0.0 0.0.0.0 240.0.0.0 U 0 0 0 eth0
0.0.0.0 195.23.75.1 0.0.0.0 UG 0 0 0 eth0
$ ifconfig -a
dummy0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
BROADCAST NOARP MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
eth0 Link encap:Ethernet HWaddr 00:40:05:4F:FE:A2
inet addr:195.23.75.12 Bcast:255.255.255.255 Mask:255.255.255.0
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:552938 errors:0 dropped:0 overruns:0 frame:0
TX packets:152484 errors:0 dropped:0 overruns:0 carrier:0
collisions:23 txqueuelen:100
RX bytes:119038154 (113.5 MiB) TX bytes:12379329 (11.8 MiB)
Interrupt:9 Base address:0x2c0
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:51690 errors:0 dropped:0 overruns:0 frame:0
TX packets:51690 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:12621644 (12.0 MiB) TX bytes:12621644 (12.0 MiB)
vbcnet Link encap:Ethernet HWaddr FE:FD:00:00:00:00
inet addr:10.0.1.1 Bcast:10.255.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 b) TX bytes:490 (490.0 b)
Firewall doesn't matter, I turn it off for testing the vpn.
----------------------------------------------------------------------
"vbc" seems ok, but tinc-up on "miragaia" isn't working as expected.
-rwx------ 1 root root 753 Oct 13 21:32 tinc-up*
What am I doing wrong?
Thanks,
--
Carlos Sousa
http://vbc.dyndns.org/
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