[CentOS] Not receiving mail

Alexander Dalloz ad+lists at uni-x.org
Mon Oct 18 16:59:58 EDT 2010


Am 18.10.2010 22:38, schrieb Dotan Cohen:
> On Mon, Oct 18, 2010 at 22:34, Steve Clark <sclark at netwolves.com> wrote:
>> Hmm... I am not having any problem connecting from the U.S.
>>
>> ping 178.63.65.136
>> PING 178.63.65.136 (178.63.65.136) 56(84) bytes of data.
>> 64 bytes from 178.63.65.136: icmp_seq=1 ttl=49 time=140 ms
>> 64 bytes from 178.63.65.136: icmp_seq=2 ttl=49 time=142 ms
>> 64 bytes from 178.63.65.136: icmp_seq=3 ttl=49 time=138 ms
>>
>> telnet 178.63.65.136 25
>> Trying 178.63.65.136...
>> Connected to 178.63.65.136.
>> Escape character is '^]'.
>> ^]
>> telnet> close
>> Connection closed.
>>
> 
> Exactly the problem! It pings fine (so I know that connections can be
> established over the physical wires) and on the IP address telnet
> answers. However, telnet to port 25 (smtp) with the domain name fails.
> Why could that be?

Sorry, your problem is not DNS. The MX resolves.

But if you talk to an MTA on port 25 you must get a greeting - that does
not happen. Instead the connection hangs.

While your www server works:

~ $ telnet 178.63.65.136 80
Trying 178.63.65.136...
Connected to static.136.65.63.178.clients.your-server.de (178.63.65.136).
Escape character is '^]'.
GET / HTTP/1.0

HTTP/1.1 200 OK
Date: Mon, 18 Oct 2010 20:54:23 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Fri, 08 Oct 2010 21:00:56 GMT
ETag: "c7a1c2-28-4e88b200"
Accept-Ranges: bytes
Content-Length: 40
Connection: close
Content-Type: text/html; charset=UTF-8

<html><body>Hello, world!</body></html>
Connection closed by foreign host.

~ $ telnet sharingcenter.eu 80
Trying 178.63.65.136...
Connected to sharingcenter.eu (178.63.65.136).
Escape character is '^]'.
GET / HTTP/1.0

HTTP/1.1 200 OK
Date: Mon, 18 Oct 2010 20:55:16 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: Fri, 08 Oct 2010 21:00:56 GMT
ETag: "c7a1c2-28-4e88b200"
Accept-Ranges: bytes
Content-Length: 40
Connection: close
Content-Type: text/html; charset=UTF-8

<html><body>Hello, world!</body></html>
Connection closed by foreign host.

I expect that even being local on the server(s) and running "telnet
localhost 25" results in a hung connection.

You misconfigured your Postfix. Check your /var/log/maillog/ for startup
errors.

By any chance, did you bring down loopback or destroyed the localhost
mapping in /etc/hosts? Or you have something broken in your main.cf.
Post the output of "postconf -n".

Alexander




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