POSTFIX Email Can't Receive External Email

rkibui · 02-19-2009, 11:43 AM

Hi Guys,
I am newbie in linux. I installed postfix using dovecot on ubuntu 8.10. I can send emails internally and externally but i cant receive any emails from an external source (eg. gmail). My ISP blocks port 25 and they told me in order for a mail server to work properly, it also needs to have a static ip (do I need to do this)? I have disabled the firewall and spamassassin isnt installed on my system. There are no message filters.
I have followed the docs available online but i cant seem to make any headway. Does anyone know how to make postfix use a specific port say 587? How can I check which port postfix is using to receive email?

kind regards

Richard

linuxlover.chaitanya · 02-20-2009, 04:08 AM

Isnt postfix a SMTP server that is used to send the mails?

rkibui · 02-20-2009, 11:44 AM

It is Wietse Venema's mailer that started life at IBM research as an alternative to the widely-used Sendmail program. more info is located at http://www.postfix.org/start.html.

I have got more info on my problem, this is error i'm getting when i try to send myself an email "The email account that you tried to reach does not exist."

linuxlover.chaitanya · 02-20-2009, 10:59 PM

That error is self explanatory and you should check with it first. I know what postfix is but I do not have much experience with mail servers.

billymayday · 02-20-2009, 11:15 PM

Are you trying to send or receive on an alternative port? In either case, how are other mailservers going to know what port to use?

Have you asked your ISP if they will open inbound port 25 traffic for you, and you should then be able to relay outbound mail through their mailserver (which isn't a bad idea anyway)?

A simple

Code:

netstat -nalp  | grep master | grep "LISTEN "

should tell you what postfix is listening on

To make postfix listen on a different port, a line like

Code:

IP_address:port      inet  n       -       n       -       -       smtpd

in place of

Code:

smtp      inet  n       -       n       -       -       smtpd

in master.cf will work. You may be able to simply replace smtp with the port number in the second version (without the IP), but I've never tried it.

Simply sending on a different port will achieve nothing, since other servers won't be listening. if you want to relay through a specific server, you can use

Code:

relayhost mailserver.example.com:port

in main.cf

rkibui · 02-22-2009, 05:45 AM

Hello billymayday,
Thanks for the info.
I figured as much, if incoming port 25 is being blocked by the isp it wont matter which other port i use to send (i thought there was a work around). I tried out netstat -nalp | grep master | grep "LISTEN " and it is listening on 25. I will have to talk to my isp and see whether they can open inbound port 25 for me or try the relayhost option.

Thanks for your info, much appreciated

kind regards

Richard