[CentOS] Sending Email Via Telnet

Tue Oct 16 21:25:15 UTC 2012
Alexander Dalloz <ad+lists at uni-x.org>

Am 16.10.2012 22:57, schrieb Cliff Pratt:
> On Wed, Oct 17, 2012 at 8:40 AM, Blake Hudson <blake at ispn.net> wrote:
>> Alexander Dalloz wrote the following on 10/16/2012 1:41 PM:
>>> Am 16.10.2012 20:13, schrieb Les Mikesell:
>>>>>> ]# netstat -pant|grep ":25"|grep LISTEN
>>>>>> tcp        0      0   *                   LISTEN      14058/master
>>>>>> tcp        0      0      *                   LISTEN      14058/master
>>>> Something is clearly going wrong.   Try 'strace -p 14058' (the process
>>>> currently listening) in one window while you telnet in another.
>>> Before tracing anything (processes or network traffic) the OP should
>>> check the maillog. It for sure will the the truth about what is going on.
>>> Alexander
>>   +1
> The OP did say a few messages above that there was nothing in the logs.
> Cheers,
> Cliff

Sorry, I must have missed that part.

But it really cannot be that a `service postfix restart' does not send
anything to syslog(). If the /var/log/maillog keeps silent, then either
the OP has damaged syslogging or he has a bigger problem.

It must be ensured that logging works. Then besides watching the mail
logfile I suggest to observe other vital logs as well, such as messages,
audit.log and bind logging in case a local nameserver is running.

My wild guessing is that Postfix misbehaves because there is a problem
with name resolving. A typical cause would be because /etc/hosts has no / localhost mapping. So checking /etc/hosts, /etc/resolv.conf
and the self-identification of the system (hostname) is important.

Hope it helps.