[clue-tech] Network Woes

[David L. Anselmi]

Todd A. Gibson wrote:
[...]
> Symptoms:
> I lose the ability to make new connections through the DSL modem
> (either into or out of my server).  New connections include Web
> queries, ssh, telnet, ftp, etc.  Also during this time some LAN
> traffic is hamstrung.

Seems likely that the LAN issue is BIND failing at reverse lookups.  Or 
it could be sshd doing the reverse lookup and BIND not answering (ping 
won't do a reverse lookup but sshd will for logging).

The modem issue sounds like it stops adding entries to the NAT tables. 
Do you have any way to look at logs or NAT maps on the thing?  Does it 
behave normally otherwise (you can ping it, get to its management 
service, etc.)?

If you capture (tcpdump, ethereal) a connection attempt when the modem 
is hung what do you see?  Probably packets going out and being retried 
with nothing coming back, but maybe there's a hint.  What other traffic 
do you see when making the connection attempt?  DNS and ARP you'd 
expect, anything else might be a hint.

(I see my machine doing AAAA lookups (IPv6) but answers come back so it 
doesn't seem to hurt anything.)

Dave