ssh stop answering requests

I have trouble with ssh external requests, however I do not have problem in the network

I have two networks, with two debian etch and two different routers ...

router 1>> network 1>> debian 1 with shorewall operating>> ssh stop answering randomly from the Internet, this happens when I connect to router 2>> network 2>> debian 2 by ssh, once I'm connected, I launch a ssh from debian2 to debian1 (which does not answer the external ssh requests just at that moment, but it does in the local network, which makes me discard any problem with the ssh service) what is surprising is that if I do, for example a w3m barrapunto.com and the site doesn't load, although I can load other sites .. allright, then the 'dns inspiration' comes again, I can browse to barrapunto and the external ssh requests go back to normal condition, it means that it answers and works perfectly ... may be related to the dns problem that sometimes stops the translation? I think that the router gets 'saturated' when it doesn't know how to translate the names and does not admit external ssh connections .... has something similar happened to someone? is quite odd but always match one thing with the other.

I also want to comment that I have stopped the avahi-daemon and in the /etc/ssh/sshd_config I have the value 'UseDNS = no'

thanks in advance

 

This looks like a firewall problem to me...

 

interesting when it is apparent that the "bug" at once (for testing do) one of the ips deny public access to fixed permitted by the user chrooted ssh and sftp by immediately iptables DROP shows me the connection, I guess that to make the router works DROP, summarizing that for a lot more things involved ACCEPT .. accept connections port 22, dns query's (obviously) and the authentication system, so maybe the router is currently being hung

 

I have another problem when it is launched after a ssh login to the server I was hung, summarizing an ssh-vvv launched against the server and I was frozen after putting the password>> debug2: channel 0: open confirm rwindow 0 rmax 32768, no access to the bash...if not all may be associated with the same problem...buf!

 

are you sure that the ssh service is running ?

 

yes, ssh is running.

 

Seems to be a problem with IPv6 enabled which brings the 2.6 kernel, you lose requests for DNS, FTP and SSH, I disabled IPV6 in / etc / modprobe.d / aliases and apparently it works now, but wait 24 hours to make it test and see if this really the problem.

 

IPV6 is a problem, since I disabled ssh requests always work, testing few days but everything ok, the only problem is that occasionally when he launched the petition and get the pass ssh I continually being stopped terminal with msg 'debug2: channel 0: open confirm rwindow 0 rmax 32768' ...