1) Postfix has NO impact on telnet. If you cannot telnet outbound to a
remote port 25 the problem is that something on your host is blocking
port 25 or something upstream from you is blocking port 25.
Can you perform the following:
telnet localhost 25
If this works, you CAN telnet to port 25 locally.
Then try a known Good SMTP server, such as Google:
# nslookup -q=MX gmail.com
Server: 209.172.41.202
Address: 209.172.41.202#53
Non-authoritative answer:
gmail.com mail exchanger = 5 gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 30 alt3.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 20 alt2.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 10 alt1.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 40 alt4.gmail-smtp-in.l.google.com.
Authoritative answers can be found from:
alt3.gmail-smtp-in.l.google.com internet address = 173.194.70.27
gmail-smtp-in.l.google.com internet address = 173.194.76.26
alt4.gmail-smtp-in.l.google.com internet address = 173.194.69.27
alt1.gmail-smtp-in.l.google.com internet address = 173.194.66.27
alt2.gmail-smtp-in.l.google.com internet address = 74.125.136.27
[root@cl-t159-360cl ~]# telnet gmail-smtp-in.l.google.com 25
Trying 173.194.76.26...
Connected to gmail-smtp-in.l.google.com (173.194.76.26).
Escape character is '^]'.
220 mx.google.com ESMTP a3si2597941qao.15 - gsmtp
quit
Connection closed by foreign host.
Make sure you actually have a service sunning on port 25, i.e.:
netstat -an | grep 25
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN
i
Make sure you do not have the inet service set to private in your master.cf:
When I first started troubleshooting I got an error in the /var/log/maillog
Jan 30 11:34:45 list postfix/master[20710]: fatal:
/etc/postfix/master.cf: line 40: inet service cannot be private.
went into master.cf
found this
"smtp inet - - n - - smtp"
Changed first "-" to n
"smtp inet n - n - - smtp"
restarted post fix worked.
Hope it helps.
On 2/20/2014 9:31 PM, Feel Zhou wrote:
Hello, My friend
This is Tom, I'm sending my greeting from China.
Today, one of my postfix server can not telnet any other mail server's
port 25. It's working before 9:00am(bejing time CHina), I have restart
the mail server and reinstall the postfix. but it's looks like not
working. How can I fix this problem. Thanks for your help
TOM
--
Eric Kimminau, Troop #284 Recruiting
e...@kimminau.org
cell: 248-766-5353
home: 248-393-8036
