The default sendmail.cf file no-longer seems to include the 'domaintable' feature, even though the sendmail package includes /etc/mail/domaintable. It seems to have gone missing from the redhat.c4 file completely for the 6.1 distro.
I can confirm that sendmail-8.9.3-10 (RH6.0) and sendmail-8.9.3-15 (RH6.1) were both missing the domaintable entry in /etc/sendmail.mc and related section of /etc/sendmail.cf. I added FEATURE(`domaintable',`hash -o /etc/mail/domaintable') to sendmail.mc and rebuilt the sendmail.cf. According to a document I read on sendmail.org, the default location of the domaintable is /etc/domaintable, so you have to include the second parameter. Note that there's a typo in line 3 of the sendmail.mc: thie ->
This is a sysadmin issue. We can not be possibly turning on all the features sendmail has to offer. The site admin is responsible for configuring the extra features. It would be cool toi have a config tool, but until then...
The issue isn't that 'domaintable' is simply missing. I can appreciate that you can't, and probably shouldn't, turn on every possible feature. The issue is that it USED TO BE enabled in at least redhat-5.2, and is no- longer enabled. You will be getting issues with folk that have used domaintable in redhat-5.2, but when they upgrade to redhat-6.1 (as all good redhatians should, yes?? ;) something will stop working. That's gonna be a very hairy one to figure out for those folk. (Not everyone's a sendmail guru ;)