misc/52240: Maliing list do not seem to accept mails with the '+' character in them

[oliver%bugabinga.net@localhost]

>Number:         52240
>Category:       misc
>Synopsis:       Maliing list do not seem to accept mails with the '+' character in them
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed May 17 19:15:00 +0000 2017
>Originator:     Oliver Jan Krylow
>Release:        
>Organization:
>Environment:
>Description:
When trying to register to the NetBSD Users mailing list with the email "oliver+netbsb-users%bugabinga.net@localhost", Majordomo responds with an error saying that "oliver+netbsd-users@bugabinga" (notice the missing .net) is not a valid email address. Which is correct, yet an error ;).

I am not sure if '+' is strictly allowed to be part of an email address, but this scheme is sometimes used for tagging in order to automatically sort mail.
>How-To-Repeat:

>Fix: