*** /tmp/,RCSt1a10548	Mon Sep 29 18:00:42 1997
--- aliases.cf	Wed Jun 11 16:06:33 1997
***************
*** 256,261 ****
--- 256,279 ----
  		;;
  	esac
  
+ 	# We disallow mail to special accounts, for convenience.
+ 	# No mail to UUCP accounts, for example.
+ 	*_*)		return (((error nosuchuser "$user" $attr))) ;;
+ 	esac
+ 	# More special custom hack: toss any invalid usernames. This is
+ 	# normally done by the local delivery channel, but frankly if we
+ 	# do it here we can reject bad destinations in SMTP traffic.
+ 	a=$(homedirectory "$user") || return (((error nosuchuser "$user" $attr)))
+ 	# this works because homedirectory returns false if the user is not in
+ 	# the local password file, whereas login2uid just gives us some
+ 	# random bogus UID.
+ 
  	case x$POBOX in
  	x)	db add expansions "$key" local
  		return (($quad)) ;;