Sendmail configuration
 

Sendmail is driving me up the wall! I have set up pretty much the standard Red Hat 9 sendmail.cf file. I have removed the smart smtp filter as I will get get my server to send all mail directly. I also changed the LOCAL_DOMAIN parameter to be lapcon.co.uk which is my domain. My DNS records are correct.

At first I forgot to open up TCP port 25 which meant that when I sent emails from my work email I would eventually get them back saying that they had too many headers and that the possible cause was a loop.

I opened up port 25 on my firewall and started to receive the emails that I had sent. I had sent them from my work email and they all got rejected with a 550 relaying not allowed. The sender was external233.toyota.co.uk which is where I work.

I have googled for the answer but feel I am not understanding a major priniciple. I wouldn't want external233.toyota.co.uk to be able to relay through my SMTP as that would mean anyone could connect from there and send emails through my SMTP.

What does need to be able to relay 127.0.0.1, localhost, lapcon.co.uk??????

I am sure once I understand this it will be easy

Make sure you add your domain to the local-host-names file.

Re: Sendmail configuration
 

basically, sendmail will relay localhost but you will need to add your domain name in access sile located in /etc/mail/access. SEndmail will checked the access file what domains need to relay.