[Mailman-Users] Periods in user email addresses rejected

[Jay Deiman]

I just got mailman up and running with Postfix and everything has been 
working perfectly except when someone tries to subscribe to the list 
that has a period in the "user" portion of the address.  For example: 
fname.lname at domain.org.  It gets rejected as an invalid email address by 
the web interface.

First, is this a setting somewhere that can be changed?  I've searched 
through the administrative settings and can't seem to find it.  I've 
also looked through the FAQs and can't find any reference to this issue. 
  I've tried Google, to no avail.  I would imagine that I'm not the 
first to pose this question...

Second, if there isn't an actual setting for this, please point me in 
the direction of the source file responsible for the (what I assume is 
an) email address regex so I can change this behavior.

Thank you,

Jay Deiman