can't access a remote server via ssh

shemeza · 03-07-2013, 08:27 AM

hi,
i'm trying to send my public key(id_rsa.pub) to a remote server(172.18.3.255) without success. i used the below command
ssh-copy-id -i ~/.ssh/id_rsa.pub root@172.18.3.255

and the output was this:
ssh: connect to host 172.18.3.255 port 22: Connection timed out.

can anybody help me out?

thnx

shivaa · 03-07-2013, 08:29 AM

Ping it and check if it's alive & reachable:

Code:

~$ ping 172.18.3.255

dinakumar12 · 03-07-2013, 08:33 AM

If its pinging do telnet 172.18.3.255 22

druuna · 03-07-2013, 08:35 AM

Also check to see if the port ssh listens on is actually 22:

Code:

nmap 172.18.3.255

(or if you have root access to 172.18.3.255):

Code:

netstat -pln | grep "sshd"

lleb · 03-07-2013, 10:07 AM

Quote:

Originally Posted by shemeza

and the output was this:
ssh: connect to host 172.18.3.255 port 22: Connection timed out.

The computer is telling you that SSH is either not running, or it is not running on port 22. That or at the very least port 22 is blocked between you and the remote computer.

nmap is your friend for seeing if port 22 is open:

Code:

nmap -p22 <IP_of_Target_here>

That is the first thing you need to run. after that you will need to look into the ssh.conf of the remote system to see if its port has been changed, then if not you need to make sure it is running.

shemeza · 03-08-2013, 02:51 AM

i run the command "nmap -PN22 172.18.19.183" and the output was

Nmap scan report for 172.18.19.183
Host is up.
All 1000 scanned ports on 172.18.19.183 are filtered
Nmap done: 1 IP address (1 host up) scanned in 201.35 seconds

but still i'm not able to ping the 172.18.19.183

Rumata · 03-08-2013, 03:05 AM

Must be a firewall problem then.

shemeza · 03-12-2013, 04:14 AM

i manage to ping the server but i still have the same output when it's about to copy my id_rsa.pub to the server, "connection time out"

jschiwal · 03-12-2013, 04:35 AM

What do you mean by remote server. The address 172.18.19.183 is a private address. Is the server on your LAN?

If the server isn't on your local LAN, you need to go through the destination's firewall via its Internet IP address, which needs to forward port 22 to the server.
If the server has an interface connected directly to the internet, then you need it's Internet IP address.

rahul.sed · 03-12-2013, 05:37 AM

check the iptables rules

lleb · 03-12-2013, 07:43 AM

Quote:

Originally Posted by shemeza

i run the command "nmap -PN22 172.18.19.183" and the output was

Nmap scan report for 172.18.19.183
Host is up.
All 1000 scanned ports on 172.18.19.183 are filtered
Nmap done: 1 IP address (1 host up) scanned in 201.35 seconds

but still i'm not able to ping the 172.18.19.183

Im not sure what the confusion is shemeza? The output of nmap flat out told you that port 22 is blocked. You either have to configure the firewall, or get whom ever is in charge of that system to grant you permission to ssh in. You will ALWAYS continue to have the same error msg. until you resolve this issue.

It can be caused by one of two things, mainly that is:

1. firewall issues (either hardware or software to include but not limited to iptables)
2. ssh is not running on that server therefore port 22 is not open.

shemeza · 03-18-2013, 03:51 AM

i managed to connect, now it's ok