AW: SSH did not work on every IP on debian x64

[Robert Menger <rm@keyweb.de>]

Hello,
thanks for the hint


But the result shows that the network shall be perfect:


[~] [18:28:47]|-->: tcptraceroute 87.118.90.150 22
Selected device eth1, address 87.118.110.118, port 50066 for outgoing packets
Tracing the path to 87.118.90.150 on TCP port 22 (ssh), 30 hops max
 1  vl1.c6500th.keyweb.de (193.22.254.1)  0.469 ms  0.322 ms  0.248 ms
 2  te1-1.c6500c1.keyweb.de (95.169.160.37)  0.246 ms  0.274 ms  0.230 ms
 3  vl4006.c6500nw.keyweb.de (95.169.160.46)  0.709 ms  0.397 ms  0.306 ms
 4  ns.km37111.keymachine.de (87.118.90.150) [open]  0.192 ms  0.243 ms  0.188 ms
You have new mail in /var/mail/root
[~] [18:28:57]|-->: ssh 87.118.90.150
ssh_exchange_identification: Connection closed by remote host



I try strace, but as network-admin I'm not quite familiar with this. When I start the ssh deamon with strace (strace /etc/init.d/sshd start), it shows only the systemcalls while starting, but then strace exits because the startup is finished. When I put strace on one of the PIDs of SSH it ends after some seconds, because the childs start on a new connection as it seems. 


What now? 


kindly regards


>Hi, Robert.
>
>Try tcptraceroute . Works as regular traceroute (adding the TCP port you want to probe as the last parameter), but it uses TCP SYN/ACK instead >ICMP, so you can check if any router on the way is blocking the traffic.
>
>Good luck.
>
>> Hello,
>>
>> as it seems, there is a problem with some IPs.
>>
>>
>> Problem Description:
>>
>> Debian x64 Lenny 5.04
>>
>>
>> - base install, without any additional packages, only IPs configured
>> - with some special IPs, SSH is not working on Port 22 ->  "server unexpectedly closed the network connection"
>> - when we change the SSH port, ssh works
>> - when we change the IP, ssh works on port 22
>> - when we configure this suspicious IP on a completly other server, 
>> the same problem occures
>> - we have checked for network problems, but all ACLs are correct, not 
>> one switchport or ACL on the core switches is configured for this IP
>>
>>
>> this are the two IPs, where SSH did not work on port 22
>>
>>
>> 87.118.90.150
>>
>> 95.169.186.3
>>
>>
>>
>> we have no ideas... we hope you have?
>
>Diego Rodríguez González
>Ferrocarriles de Via Estrecha
>Dpto. Telecomunicaciones y Sistemas Informáticos
>diego@feve.es	(+34)985981778 ext. 99004 / (+34)660574762