unable to send mail to gmail

[adv]

it always returns

Apr 22 02:34:12 server-name postfix/smtp[3920]: connect to gmail.com[64.233.161.83]: Connection timed out (port 25)
Apr 22 02:34:12 server-name postfix/smtp[3945]: connect to gmail.com[72.14.253.83]: Connection timed out (port 25)

Is there any idea to fix?
Thank you.

[uxbod]

can you telnet to port 25 on the remote server ?

[fviero]

Timed out connections are more than often an indication of a firewall blocking these connections. Another common one is the "connection refused" error, this one is sympton that the service in question is not running on the host you´ve attempted to connect.

[adobrin]

your DNS server is returning the wrong MX host

try this from the command line, on the mail server:

adam@stylin:~$ nslookup
> set type=MX
> gmail.com
Server: 10.2.1.5
Address: 10.2.1.5#53

Non-authoritative answer:
gmail.com mail exchanger = 50 gsmtp183.google.com.
gmail.com mail exchanger = 5 gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 10 alt1.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 10 alt2.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 50 gsmtp147.google.com.


you should get similar results. (not "gmail.com")

[fviero]

your DNS server is returning the wrong MX host

Right, but what could make a DNS server return such a result? A rogue entry in a hosts file? DNS server misconfiguration (ok, but what misconfiguration?). Anyway, adobrin is correct. None of those IP listed at the top of the thread answered to connections on port 25. But those listed as MX records for the nslookup query did their job very well

telnet gmail-smtp-in.l.google.com 25
220 mx.google.com ESMTP i39si13101889wxd.27

So, recheck your name resolution services

[adobrin]

ooh look
Sudden Outgoing DNS (MX) Lookup failure

"do you have DNS lookups disabled in your MTA?"

-> " *sheepish* That'd be the problem...I misinterpreted the meaning of that checkbox. "