Cant connect to Centos via Putty using ssh. Error name unable to resolve

Uva18 · 08-08-2013, 12:20 AM

i Cant connect to Centos via Putty using ssh. Error name unable to resolve. i have enable the firewall setting on port 22 ssh tcp & udp. It worked once then the following time, its giving "temporary unable to resolve host name". i tried putting i.p but same error. pls help

ilesterg · 08-08-2013, 12:53 AM

Did you try ping to the remote CentOS host?

Uva18 · 08-08-2013, 01:34 AM

yes, i am able to connect via putty using telnet but not ssh. earlier when i entered 192.168.1.9:1, it was able to go in. then i closed the session & now i cant login. the service is started.

chrism01 · 08-08-2013, 07:22 PM

'Unable to resolve...' means it can't find a DNS entry to convert hostname to ip addr. You should be able to connect via ipaddr using telnet or ssh, unless its firewalled off.

lleb · 08-08-2013, 08:23 PM

Quote:

Originally Posted by chrism01

'Unable to resolve...' means it can't find a DNS entry to convert hostname to ip addr. You should be able to connect via ipaddr using telnet or ssh, unless its firewalled off.

yup what chrism01 stated. this means your MS Windows computer does not know the NAME of your CentOS box.

in the putty setup window use the IP, not the URL/FQDN and also do not use port 1, use standard port 22.

This is 100% an issue of the computer you are running Putty on, not your CentOS box, or ssh.

ilesterg · 08-08-2013, 09:51 PM

Quote:

Originally Posted by Uva18

yes, i am able to connect via putty using telnet but not ssh. earlier when i entered 192.168.1.9:1, it was able to go in. then i closed the session & now i cant login. the service is started.

Are you using the IP address everytime? I looks strange since you can telnet but not ssh. Then there's your DNS issue. I'd like to think of these as separate problems.

Uva18 · 08-10-2013, 01:40 AM

Yes i am using ip address. I disabled the firewall & antivirus. still the same. i am currently using tightvnc to login to make certain changes. others via telnet. i am new to this but most rules in windows,mac or linux all runs the same basics(linux mostly).
its not an issue but i want to figure out why i cant connect using ssh port 22. it by right should'nt. i tried to modify the setting in konsole but permission denied (even in root). Dumb question...could it be blocked by other software like zpanel or mebuzo?

lleb · 08-10-2013, 11:06 AM

Quote:

Originally Posted by Uva18

Yes i am using ip address.

you will NOT get a "Error name unable to resolve" if you are using IP address. This as i clearly stated above is a DNS issue in Windows. Add the NAME you are using along with the IP to your MS Windows host file. typically located C:/Windows/System 32/host, you will need to do this with admin rights and you will need to be able to view hidden files.

It should look something like this:

Code:

#	127.0.0.1       localhost
#	::1             localhost
192.168.5.125		server
192.168.5.201		user1
192.168.5.209		user3
192.168.5.100		user2
192.168.5.220		user4

After you have done that, reboot your MS Windows computer and you should be able to resolve names properly to your CentOS server.

Quote:

i tried to modify the setting in konsole but permission denied (even in root).

What permissions were you trying to modify? You have to be careful when you start mucking around with system permissions like ssh and sshd.

You still have not told us what vs of CentOS you are running, but im going to go out on a limb here and guess it is semi modern, meaning v 5.x or 6.x, and that you have not changed SELinux settings from enforcing to permissive.

http://www.cyberciti.biz/tips/enable...g-purpose.html

there is a very simple way to put SELinux in permissive. NEVER disable SELinux.