[GRLUG] No connectivity between two specific end-points

[Ben Rousch]

Have you tried turning it off an on again?

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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-- 
 Ben Rousch
   brousch at gmail.com
   http://clusterbleep.net/