telnet: Unable to connect to remote host: No route to host
 

Am troubled by the fact that telnet works only for port 25 but not 110. The troubling thing is how the telnet test for 110 would say there's no route when it's fine for port 25. Any idea?

[test@backup ~]$ telnet <IP v4> 25
Trying <IP v4>...
Connected to <IP v4> (<IP v4>).
Escape character is '^]'.
220 production.domain.com ESMTP Postfix
^]
telnet> quit
Connection closed.
[test@backup ~]$ telnet <IP v4> 110
Trying <IP v4>...
telnet: connect to address <IP v4>: No route to host
telnet: Unable to connect to remote host: No route to host

Hi,

It could be either a firewall blocking port 110, or a router that does not forward port 110 to an internal box.

This is due to IPtables blocking port 110. The default REJECT statement on alot of installs is:

REJECT --reject-with icmp-host-prohibited

And the 'icmp host prohibited' response displays as "no route to host" on the client side machine.

All you need to do is open port 110 on IPtables.

That's exactly it. I thought by turning on Mail (SMTP) it'd open both ports 25 and 110. I had to add port 110 separately. Thanks.