[CentOS] setting up postfix

[Craig White]

On Oct 16, 2012, at 7:02 AM, Larry Martell wrote:

> This should be an easy one. I'm trying to get postfix going. I've
> never done this before. I followed the directions at
> http://wiki.centos.org/HowTos/postfix. I opened port 25:
> 
> iptables -I INPUT -p tcp -m tcp --dport 25 -j ACCEPT
> 
> Here's an attempt to send mail:
> 
> [motor at localhost motor]# mail -v larry.martell at gmail.com
> Subject: test
> test
> .
> EOT
> larry.martell at gmail.com... Connecting to [127.0.0.1] via relay...
> 220 localhost.localdomain ESMTP Postfix
>>>> EHLO localhost.localdomain
> 250-localhost.localdomain
> 250-PIPELINING
> 250-SIZE 10240000
> 250-VRFY
> 250-ETRN
> 250-ENHANCEDSTATUSCODES
> 250-8BITMIME
> 250 DSN
>>>> MAIL From:<motor at localhost.localdomain> SIZE=219
> 250 2.1.0 Ok
>>>> RCPT To:<larry.martell at gmail.com>
>>>> DATA
> 250 2.1.5 Ok
> 354 End data with <CR><LF>.<CR><LF>
>>>> .
> 250 2.0.0 Ok: queued as D26C8830F
> larry.martell at gmail.com... Sent (Ok: queued as D26C8830F)
> Closing connection to [127.0.0.1]
>>>> QUIT
> 221 2.0.0 Bye
> 
> But I don't receive the mail. In a file in /var/spool/postfix/defer I see:
> 
> <larry.martell at gmail.com>: connect to
> alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c00::1a]:25: Network is
> unreachable
> recipient=larry.martell at gmail.com
> offset=654
> dsn_orig_rcpt=rfc822;larry.martell at gmail.com
> status=4.4.1
> action=delayed
> reason=connect to
> alt2.gmail-smtp-in.l.google.com[2607:f8b0:400d:c00::1a]:25: Network is
> unreachable
> 
> Have I missed a step or done something wrong?

----
most home broadband providers block outbound port 25 from reaching any smtp servers other than the ones that they provide and typically require authentication in order to stop spam.

Craig