sendmail: sender address not found, domain rejected

[Hans-Edgar Rossa]

Hello,

when sending mails to soem addresses, we do get the following error message:

MAA14772 15 210156 Oct 9 12:11 root
(Deferred: 450 : Sender address rejected: Domain not found)
this_is_a_test@hp.com

(the real name has been replaced by this is a test just for this posting)

If we try other addresses, e.g. ansgar.luig@web.de it works.

What is wrong ?

Ansgar

[Sridhar Bhaskarla]

Looks like your domain is not propagated well. check with your DNS administrator.

-Sri

[Berlene Herren]

Sridhar is right, his error indicates the server has not been registered with the DNS. You will need to add an A record for this server to the DNS database.

You "may be" able to get around this problem by adding the address to /etc/hosts.

Berlene

[Kevin Wright]

your hostname is not known publicly, so when the mail server at hp.com does a gethostbyip, it fails. There are ways around this without making your server a public IP, which you probably don't want to do..you need to set up aliasing, or masquerading so mails sent from user@hostname.domain.com look like they are coming from user@domain.com..
Set the DM in sendmail.cf to DMdomain.com and set CE as root, so you can send emails outside your network as users OTHER than root.