[GRLUG] No connectivity between two specific end-points
megadave
megadave at gmail.com
Tue Nov 13 09:19:53 EST 2012
What does the route table on the host at 192.168.34.183 look like?
What are the IP addreses of "A" and "B" ?
On Tue, Nov 13, 2012 at 9:15 AM, Adam Tauno Williams
<awilliam at whitemice.org> wrote:
> This end: LINUX box A and LINUX box B
>
> Mystery is that "A" can ping the remote device, and perform HTTP
> connections, B cannot (no ping, no HTTP, etc...). The remote device is a
> very boring HP4200 laser printer
>
> Firewall on A & B:
>
> cassowary:~ # iptables --list
> Chain INPUT (policy ACCEPT)
> target prot opt source destination
>
> Chain FORWARD (policy ACCEPT)
> target prot opt source destination
>
> Chain OUTPUT (policy ACCEPT)
> target prot opt source destination
>
> Remote device 192.168.34.183 which lies on the other side of an MPLS 'cloud'
> [so oblivious to whatever hi-jinks the proprietary numb skulls in the middle
> pull].
>
>
> Traceroute from A [working]:
> adam at cebolla:/home/adam> sudo /usr/sbin/traceroute 192.168.34.183
> traceroute to 192.168.34.183 (192.168.34.183), 30 hops max, 40 byte packets
> using UDP
> 1 router.example.com (192.168.1.6) 0.864 ms 0.538 ms 0.585 ms
> 2 172.20.42.102 (172.20.42.102) 2.175 ms 1.980 ms 2.231 ms
> 3 12.84.15.221 (12.84.15.221) 7.391 ms 7.292 ms 6.843 ms
> 4 cr85.cgcil.ip.att.net (12.122.85.102) 20.248 ms 19.627 ms 19.046 ms
> 5 cr1.cgcil.ip.att.net (12.122.99.33) 22.327 ms 21.691 ms 21.584 ms
> 6 cr82.gdrmi.ip.att.net (12.122.152.6) 18.671 ms 18.115 ms 19.772 ms
> 7 12.112.209.37 (12.112.209.37) 12.450 ms 12.352 ms 12.230 ms
> 8 12.112.209.38 (12.112.209.38) 16.428 ms 17.401 ms 17.632 ms
> 9 192.168.34.183 (192.168.34.183) 15.715 ms 15.978 ms 16.346 ms
>
> Traceroute from B [not working]:
> adam at cassowary:~ # sudo /usr/sbin/traceroute 192.168.34.183
> traceroute to 192.168.34.183 (192.168.34.183), 30 hops max, 40 byte packets
> using UDP
> 1 router.example.com(192.168.1.6) 0.621 ms 0.646 ms 0.695 ms
> 2 172.20.42.102 (172.20.42.102) 2.290 ms 2.239 ms 2.404 ms
> 3 12.84.15.221 (12.84.15.221) 7.355 ms 8.100 ms 7.851 ms
> 4 cr85.cgcil.ip.att.net (12.122.85.102) 20.735 ms 20.269 ms 19.558 ms
> 5 cr1.cgcil.ip.att.net (12.122.99.33) 22.579 ms 22.115 ms 20.127 ms
> 6 cr82.gdrmi.ip.att.net (12.122.152.6) 18.181 ms 18.653 ms 18.080 ms
> 7 12.112.209.37 (12.112.209.37) 13.358 ms 12.310 ms 12.216 ms
> 8 12.112.209.38 (12.112.209.38) 16.149 ms 16.217 ms 16.486 ms
> 9 * * *
>
> Hmmmm. Host B can reach and communicate with every other host on the remote
> subnet. The remote router [12.112.209.38] is a Cisco 2800 that doesn't do
> any packet filtering [only QoS].
>
> Guesses / thoughts as to what might be eating the packets for this very
> specific pair of end-points?
>
>
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