Ok, I’m an old Sendmail dog. My experience with sendmail has been on the whole very positive. Let’s face it, it is horribly complex, but has all the features you could ever want. Most of the time finding an answer to a problem is just a quick google away, but not always.
I recently upgraded my home machine from Mandrake 8.0 to Gentoo. The box hosts a couple of domains as well as a some web apps. One of them sends out e-mail. For the last few weeks I noticed that Sendmail was adding a X-Authentication-Warning header to messages sent by the web user. In essence this says that the mail was sent by a user other than what it says on the From header.
This is generally useful in tracking people who spoof e-mail, but not so desirable for legitimate users, such as my web server.
Sendmail has provisions to allow trusted users for whom this warning header is suppressed and so I added the userid under which the web server runs to the /etc/mail/trusted-users file. Without any result.
It took me some time to figure out the /etc/mail/sendmail.cf is consulted by the daemonized sendmail process only. When e-mail is sent via command line sendmail instance it is not. In this case sendmail looks at /etc/mail/submit.cf instead. That’s where I got bitten. I had to add the following line to my submit.mc file
This told sendmail to consult /etc/mail/trusted-users for command line invocation as well.
sigh … the things you learn. lol