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Accessing CENTOS machine using SSH

+2 votes
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I have a CENTOS 5 box that can reach the internet and can ping to/from all windows system on my home network. The catch is that I can not connect to the box using SSH from any windows machine, though they can easily ping the linux box and vice-versa.

posted Oct 1, 2013 by Jagan Mishra

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Is there a firewall running on the Linux machine, and if so, is it  allowing tcp port 22 through? Are you able to ssh from other Linux  systems on your home network (if there are any) or have you only tried  sshing from Windows systems? Is sshd running?
I will check on firewall, though I have not deliberately activated one. This machine has run for several years without this occurrence. I will check on port 22. All other machnes on the LAN are Windows.
Surprisingly (to me, anyway), the SSH daemon is off by default in CentOS; you need to 'chkconfig sshd on' and 'service sshd start' as root in order to be able to ssh in.

2 Answers

+1 vote
 
Best answer

Others have mentioned it as well, it sounds to me like there's a local firewall (probably iptables) running on the linux box. Although I thought the default in the 5 series of redhat/centos was to leave port 22 open. it could also be that you don't have the ssh daemon turned on/possibly even installed (?)

I'd make sure you have ssh turned on (from the linux machine, ssh to localhost, telnet localhost 22, ps -ef | grep sshd, service sshd status, chkconfig --list | grep ssh ) if all that works and looks OK, then try turning off firewall (service iptables stop) then try to ssh in from your other machines if that's ok, then back to the linux machine's console and do

service iptables start
iptables -I INPUT -s ${cdir of your lan[1]} -p tcp --dport 22 -j ACCEPT
service iptables save

and I'd think you should be set.

[1] if your LAN is 192.168.0.0 with a netmask of 255.255.255.0 the CDIR would be 192.168.0.0/24, not sure how much you've dealt with that. Google will be your friend if you have an odd netmask.

some of these options may be off, I don't use centos 5 much these days and all I'm putting in here is from memory, so I might be missing some stuff, but I think it's reasonably close.

answer Oct 1, 2013 by anonymous
+1 vote

The catch is that I can not connect to the box using SSH

That's obviously not true or just half of the story. Did you actually try *sshing* in? Your title mentions sftp, not ssh. So, what software are you using to connect? I would normally recommend using SCP (and not sftp) with WinSCP. If you do that you can have the sftp subsystem of OpenSSH shut off.

answer Oct 1, 2013 by Seema Siddique
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