TIMEOUT doesn't always work If a shell is invoked then procmail may wait while executing a command for longer than TIMEOUT specifies. regexp matching bug Some regexps may return an incorrect value in the MATCH variable. In particular, this can happen when 'redundant' * or + operators appear on the lefthand side of the \/ token. Incorrect usage of -lnsl and -lsocket libsocket and libnsl should be avoided if not needed as they're broken under at least one version of IRIX. If your procmail binary doesn't reliably find user's home directories, or otherwise appears to have problems accessing the passwd file, try removing -lnsl and -lsocket from the SEARCHLIBS variable in the Makefile, then recompile.