[Mailman-Users] domain equivalence

[Toby Butzon]

Hi all,

Here's my situation:

a.example.com runs mailman.
b.example.com hosts 90% of a.example.com's subsriber's addresses
   (i.e., 90% of my subscribers have foo at b.example.com email addresses).
c.example.com is a legacy system now setup to forward all incoming
   mail to the newer b.example.com system. Many users from the old system
   still prefer their foo at c.example.com address and continue to use it.

So, effectively, a mail account foo at b.example.com is reachable as either
   foo at b.example.com, or
   foo at c.example.com

Obviously, if we turn on "subscribers only" posting on a list, people posting
from c when subscribed as a b user gets his messages held for
approval.

Additionally, users can send mail via multiple interfaces -- secure shell into
c (which still shows their from host as c), a webmail system on
b (which uses a from host of b), and remote SMTP clients (and
users can "correctly" set it up to use either b or c). The point of
all this detail is to make the point that users are *not* incorrectly
subscribed; rather, because the configurations are out of their hands, they
become constricted to using one or the other, or wait for moderator approval.

I don't know what the optimal solution would be, but my first guess would be
to add a way to "alias" domains so that b and c are seen as equal by
that particular filtering step. I don't know what other cases domain name
comparisons occur in, but there might be other cases where the same comparison
is desirable, and yet it might not be in all.

If there's already a good way to work around this issue, fill me in.
Otherwise, I'll have to see about coming up with a workaround myself (probably
using the method I just described) -- but before I do, I'd like to hear any
comments you have about whether that's the right way to go about fixing the
problem.

Thanks in advance.

-- 
Toby Butzon