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I can successfully connect to Debian via SSH.
The problem is that after a while — one or two days I think — it depends on the number of times I connect, I cannot connect remotely... only locally. The machine must be restarted in order to reconnect.

I haven't seen the error myself yet, as they restart it at 4am in the morning and I am not there, but it is like "networking down" ? "connection table ...something"...

Any ideas what I can do to trace/solve this problem ?

I get this also in the sshd log when it is down:

debian exim4: gethostby*.getanswer: asked for "debian IN AAAA", got type "A"

share|improve this question
Have you set TCPKeepAlive Yes in your /etc/ssh/ssd_config? And are you using a ClientAliveInterval? – jasonwryan Jun 20 '11 at 10:56
I checked the logs of sshd and it is a mess. There are tons of computers trying to connect remotely.. I think i should change port or something.. TCPKeepAlive Yes there is yes... but i havent set iptables.. ClientAliveInterval there isnt such option.. – GorillaApe Jun 20 '11 at 11:10
Change your port. The log message looks to be an IPv6 request - I don't think it is related to your timeout issue... – jasonwryan Jun 20 '11 at 11:18
This request occurs only when i have problem.. – GorillaApe Jun 20 '11 at 11:38
I guess that "I can connect only locally" means that you are no longer able to connect via SSH, only via login/physical keyboard access? If this is correct, this sounds like a DHCP problem to me: the DHCP lease for the IP address expires and your box doesn't get a new one. Can you please post the output of ip addr show when you can connect and when you cannot? – Riccardo Murri Jun 20 '11 at 12:20

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