It seems that that latest version of sendmail doesn't like executing programs from /etc/aliases except if it's majordomo.
I'm helping my roommate Rob [1] install some mailing list software. I use something other than majordomo which works for me and is rather simple to configure and use.
Only he's running Sendmail 8.9.3 and when we put the appropriate magic in /etc/aliases I keep getting back:
sh: mailserv not available for sendmail programs 554 "|/home/mailserv/bin/mailserv nnnnnnn-l request"... Service unavailable
Which is new to me.
So I'm downloading the source code to Sendmail to see why it's failing.