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uiuiui172 10-18-2009 11:55 AM

Postfix can't send or recieve mail!
I am running Ubuntu 9.04 with dovecot and postfix and i have free service with and i would like to keep it free. My dyndns hostname is and i can telnet it from localhost, internal ip
external ip, and internet hostname. I can telnet all mail ports. My ISP (comcast) does not block port 25. I can't email locally ( within my system) and i can't send or recieve email from other servers (like google). How do i get a domain? Why can't I send or recieve email? Please help me!!!!

AlucardZero 10-18-2009 12:20 PM

Why can't you send mail? What's the error message?


alucard@karrde:~$ telnet 25
Connected to
Escape character is '^]'.

There's something on port 25, but it's not acting like a mail server. What's the output of (as root)

netstat -anp | grep :25

uiuiui172 10-18-2009 05:30 PM

tcp 0 0* LISTEN 9618/master
tcp 73 0 CLOSE_WAIT -
tcp 28 0 CLOSE_WAIT -
tcp 83 0 CLOSE_WAIT -
tcp 19 0 CLOSE_WAIT -

AlucardZero 10-18-2009 05:40 PM

Ok, Postfix is listening.

uiuiui172 10-18-2009 06:27 PM

so... what do i do?

AlucardZero 10-18-2009 06:42 PM

Why can't you send mail? What's the error message?

uiuiui172 10-18-2009 10:02 PM

ok i reinstalled postfix so now i can send email locally but not to comcast or other places.

here is the error code:

host[] refused to talk to me: 554 comcast Comcast blocked. Please see

AlucardZero 10-18-2009 10:36 PM

As a Comcast residential customer, you can't send mail directly. Instead, use Comcast's SMTP server to send mail.


relayhost =

uiuiui172 10-18-2009 11:44 PM

then i get this:

<>: host[] said: 550
5.1.0 <dylan@dylanserver> sender rejected : invalid sender domain (in reply
to MAIL FROM command)

AlucardZero 10-19-2009 08:39 AM

As it says, "dylanserver" is invalid.

uiuiui172 10-19-2009 02:11 PM

how do i change it to a valid one?

AlucardZero 10-19-2009 02:37 PM

Read the manual / google / etc. I'm happy to help, but not handhold. You've got to learn how to do it yourself.

AnthonyP 11-05-2009 01:54 AM

I have to say, that was the most polite I've ever seen a hand off go.
Very nice :)

jima2 09-08-2011 12:36 AM

Here's a solution which worked for me:

http: //

P.S. Rudeness seems to be pandemic...

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