[Mailman-Users] ISO RegExp example to block bot subscribe requests

[Stephen J. Turnbull]

Woody Mon via Mailman-Users writes:

 > So I tried entering RegExp ^.*+ but Mailman rejected this entry.

That's illegal syntax for a regexp because "+" is an operator.

The version you want is "^.*\+".  However, that is a very bad idea if
you have any posters with email skills, because embedding "+" in the
return address for outgoing mail is a common way to identify the
source of incoming replies.

A more conservative regexp would be "^[a-z]+\+[0-9]+@" which will
catch the pattern of LETTERS "+" DIGITS.