[GTALUG] Connection Refused

[Steve Harvey]

On Thu, Feb 19, 2015 at 10:59:01PM -0500, Randy Jonasz wrote:
> Hello,
> 
> I have an ubuntu 14.04 server running postfix.  I wanted to test it with
> telnet on port 25.  Alas I receive connection refused errors although I
> can ssh to the server fine and see that master is listening on port 25.
> I ssh'd to another machine outside of my lan and tried telnet from
> there.  I was able to connect fine.  Does anyone have any suggestions
> how I can troubleshoot this? My hosts.deny file is empty.
> 
> Here's the server's iptables -L output.  My wan address is not listed.
> Thanks for your help!
> 
> Randy
> 
[snip]

  It is possible that the ISP that you use from home is blocking
outbound TCP/25 connection attempts?

  Try installing tcptraceroute on your home machine and see if you can 
contact any external mail servers, i.e.

# host -t MX google.com.
google.com mail is handled by 50 alt4.aspmx.l.google.com.
...
# tcptraceroute alt4.aspmx.l.google.com. 25