Relaying Denied: Proper Authentication Required???
This document applies to Fedora Core 4 and sendmail
This is the bug that has in the past driven me mad! It arises when using setting up sendmail for SMTP AUTH with either PLAIN or LOGIN! Basicly sendmail seems to negotiate the way it will AUTH with the client then it asks for the login info.
Below lies a chunk of sendmail.mc that tells sendmail how to AUTH:
define(`confAUTH_MECHANISMS', `LOGIN PLAIN')dnl
Now most of us would think thats enough but one little problem i have failed to notice over the last 22 hours (yes, i dont give up when im stuck ): is that although i was telling sendmail to use AUTH of A N Y kind it was failing! Only Outlook/Express was failing, Mozilla and Thunderbird where working fine as was local mail. This seemed to be becasue they latter mail clients where using MD5 to do AUTH but Outlook/Express seems to use plain!
A lot of googleing got me nowhere so I started at the bottom by checking the sasl libraries and noticed that there was a bunch of .so's for md5, cram, digest and such but not one for plain or login. A quick yum list | grep plain came up with cyrus-sasl-plain, a package that, once installed seemed to provide both login and plain auth mechanisms :)
So to all you people suffering the above problem, check you have the cyrus-sasl-plain package installed;
set auth_options to `A'
make -C /etc/mail
service saslauthd restart
service sendmail restart
Should get you up and running!