a server with RHEL 5.3 is running.
im going to access this via putty but get message
"server unexpectedly closed network connection". after some time.
same is the case with root and oracle user.
what can be issue ?
First thing to check is that Putty is able to get to the target and is not being defeated by some network issue. Putty may not be able to connect to the target at all and the circuit is being dropped by some network device.
Can you ping the target? If you seem to be able to, can you down the target and make sure that ping stops? Somehow, ensure that you don't have a network issue.
Are you trying to connect through telnet or ssh ? If it is ssh then run the command lsof -i :22 on the server. If the ssh daemon is listening to port 22 then server is ready. It might be connectivity issue. Do check your network connection and allow/deny file and firewall settings. Also check that ssh radio button is selected or not while opening putty.
Could that be sth like an idle timeout? There's quite some parameters in ssh_config that control timing.
First you need to make sure SSHD is set to start when you boot up. Run:
ntsysv
And check the box next to sshd.
Then you need to make sure sshd is currently running:
/etc/init.d/sshd status
If it isn't running, start it:
/etc/init.d/sshd start
Then you need to open the port in your RHEL firewall. Run:
system-config-securitylevel-tui
And check the box next to SSH to allow inbound connections.
I have seen this happen several times. Each time the problem was the same.... a second box with the same IP address. Easy to prove. Turn off the server, then ping it. If you get a response you have found the problem.
You can also 'telnet ssh_host 22' and see the prompt from the sshd.
You can query the arp cache to see the mac for the ip on each end, if they are on the same subnet. If there are two hosts on the same IP, you will see their arp responses in there. 2.1.�Address Resolution Protocol (ARP)
Did you solve the problem?