Problems with sendmail

[maaki]

I'm having some problems with Sendmail. I'm more an application developer than Linux sysadmin, and my boss gave me task which is causing me overwhelming troubles. Here is the situation.

I'm getting an error "Sender address rejected: Domain not found" when I'm trying to send e-mails via PHP script. So far what I have found out is the problem is caused that the Sendmail cannot find the server defined in headers. Lets say the hostname defined in header is server.company.com. And this has to do with MX records if I'm not mistaken?

The domain company.com exists (and can be accessed from Internet) and it is hosted on different machine that the Sendmail which is trying to send e-mails. The "server1" is located in Intranet so it can't be accessed from Internet.

The questing is:
1) Is it enough to solve the problem if DNS server's records are altered so that Sendmail can find valid a record for server1.company.com?

2) Should I edit Sendmail's settings so that I can bypass the MX check? Or Linux's setings some how to fix this?

So far I haven't found any helpful topics with Google, only topics with which I have been able to define the core problem.

Thanks for your help 🙂

[nemonoman]

I'm not Very Smart about this stuff, but here would be a baby step:
Check php.ini. There's an entry for 'sendmail'. Make sure the entry matches your severr's settings.

[NogDog]

One possibility is that many mail servers are configured to only send mail with a "From:" address which is a valid account on that server. If you do not want the email to be from such an address, you may still need to set the "From:" header to a valid address on your server, then use a "Reply-To:" header for the address you want replies sent to.