[Mailman-Users] Filter for exact domain names

[Cyndi Norwitz]

I am getting a lot of spam post attempts from a domain tom.com.  I  
would like to do an automatic discard in discard_these_nonmembers for  
this domain.

I can add this line of code: ^[^@]+@(.*\.)?tom\.com$

But I am concerned that this will discard all .com domain names that  
end with tom, which may be some legit ones.

I do not understand the code as it's different from anything I've  
worked with and the above recipe (which I mucked up several times on  
my own despite some trips to the FAQ) came from Mark.  My guess is I  
need to remove the question mark, but I'd like confirmation first.

Thanks,
Cyndi