Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am trying to telnet from Ubuntu server (running Maverick) on ec2 to another machine I have set up not on ec2 - we'll call it "server-x". Server-x is running an imap server and I am trying to test connectivity to it.

The two machines are connected via vpn. I can ping from the ec2 machine to server-x no problem. On another machine also on the vpn but also not on ec2 I can telnet to server-x without issue so it is accepting incoming connections on that port.

But when I run telnet from the ubuntu instance to server-x I get :

ubuntu@ip-10-111-11-11:~$ telnet 9143
telnet: Unable to connect to remote host: Connection refused

Other telnets work like this:

ubuntu@ip-10-111-11-11:~$ telnet 993
Connected to
Escape character is '^]'.

I have disabled ufw on the ubuntu machine. Is there anything else that can be blocking this outgoing connection? I tried adding the outgoing port to iptables but I'm not certain I'm doing that right.

Update: The service running on server-x is an imap server. When I changed it to use the traditional imap port 143 - the ubuntu machine can now telnet without problem. Why can it not telnet out on 9143?

I'm pretty sure 9143 is open and listening on server-x, when I run netstat:

netstat -an |grep 9143    
tcp46      0      0  *.9143                 *.*                    LISTEN
tcp4       0      0  *.9143                 *.*                    LISTEN
share|improve this question

Connection refused, apart from the port being blocked, may also mean that nothing is listening on that port (or that IP/interface).

Please run the following on the machine you are trying to telnet to:

netstat --numeric-ports -l | grep 9143

And paste the output as a comment, or edit it into your question. If you get no output, then there's a problem with whatever program is supposed to be listening on port 9143.

share|improve this answer
I've now changed the port the remote service is listening on and now it works. See my update. – brendan Jul 8 '12 at 14:06
Was it listening on 9143 as shown by netstat? Anyway, glad it got solved :) – izx Jul 8 '12 at 14:08
yeah it was, the remote machine is not linux, so I had to tweak my netstat but results the same – brendan Jul 8 '12 at 14:20

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.