[AuckLUG] Sendmail configuration

[Henrich Frauendorf]

Hi
Nowadays most mail servers are setup to do the following:
1.)    When a connection is made to the server (receiving server) it will first look and see if the contacting mail server (your server) has a proper domain name associated to it. So during the handshake if your server says it is localhost.localdomain, the receiver will do a DNS lookup on localhost.localdomain, obviously it won’t resolve, hence the bounced mail.
2.)    Secondly some servers will take it a step further and if the DNS resolve make sure it resolves to the IP. So it does a reverse DNS query on your IP 123.123.123.123 and want the reply to be the same as forward query.

What I would suggest is the following
1.)    Create a A record DNS name, even if it is with someone like the dyndns servers i.e. yourcompany.dyndns.org.
2.)    Create a PTR record for your IP to resolve to yourcompany.dyndns.org.. You will need to get your ISP to do this for you. 
3.)    Change your server to pass yourcompany.dynsdns.org to mail servers it sends mail to. (Unfortunately I can’t help you with sendmail)

You can also try relay mail out via your ISP’s SMTP server. If you are using something like DSL you will need to do it this way.
 
Hope this help’s. Feel free to pop me a mail if your still unsure.
 
Regards
 
Hein
 


----- Original Message ----
From: Deepan <codeshepherd at gmail..com>
To: aucklug at linux.net.nz
Sent: Thursday, 20 March, 2008 11:07:42 AM
Subject: [AuckLUG] Sendmail configuration

Hi All,
I am using sendmail via php mail function to send
emails. However few servers reject my mails with
the error 'Sender address rejected: Domain not
found', since mails from my server are sent as
email at localhost.localdomain. How do I change this
to a valid domain name ? We only own a public IP.
we dont really have a domain name, is it possible
to use IP ? 
Regards
Deepan
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Home Page: http://www.codeshepherd/ 



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