[NTLUG:Discuss] Postfix Operation

[MadHat Unspecific]

Sally Welch wrote:
> On 8/4/07, Dennis Rice <dennis at dearroz.com> wrote:
>> I am attempting to configure Postfix mail server.  I am not able to
>> send mail from a remote server, although I can receive it.
>>
>> At the moment, it is to operate exclusively in my internal network for
>> my education.
>>
>> Configuration:
>> FC6
>> Firewall disabled
>> SELinux disabled
>> Postfix configuration (main.cf)
>> mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
>> mynetworks_style = class     {this has been set to subnet}
>> myorigin = $mydomain
>> relay_domains =        {blank}
>> relayhost =              {blank}
>>
>> Installed dovecot for pop, ok and works for port 110.
>>
>> Using chkconfig, postfix is on, did restart and reload.
>> Created users.
>>
>> Had to install telnet_server, ok.
>> Can telnet to server in general, but can not telnet to port 25
>> (telnet server-IP 25).
>>
>> Performing nmap, port 25 is open.  Port 110 is open, but 220 (imap) is
>> not.
>>
>> Initially using Thunderbird on another Linux host to test, can
>> download a received file, so that part configured ok.  At this time, I
>> have set the server name to the IP address, as do not have a dns
>> server set up for this level (yet).
>>
>> I am focusing on the point that I am not able to telnet to port 25.
>> An obvious reason why mail can not be sent.  Since nmap says it is
>> open, I do not understand why I can not telnet to it.
>>
>> Can anyone provide insight to what I might be doing wrong.
> 
> Hi Dennis,
> 
> If there is no firewall, I have to think that Postfix isn't actually
> running, since the port isn't open.
> Does 'ps -ef |grep postfix' prove that it's running?  Does the mail
> log indicate that all's well?
> 

Or where is it bound?
sudo netstat -pln | grep postfix

see if it is bound to 127.0.0.1 or 0.0.0.0 or your IP.
sorry, coming in late and drinking tonigth.
220 is not imap.  143 is imap. 993 is imap/ssl.  postfix is an MTA, so
25 only.  As far as sending mail, you will need to configure the relays
hosts (not recommended), or use authentication credentials to allow
relay (recommended).  I use sendmail and exim, so I am no real help with
the configs...  so I guess I can shut up now.

I'm confused.  If nmap says 25 is open, but you can't telnet there,
problem.  nmap will do a connnect by default.  Maybe add in a -sV and
see what the results are (assuming a recent version of nmap).


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MadHat (at) Unspecific.com, C²ISSP
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