Just don't forward, and every few days send an automatic
mail to the old list saying where the new list location is
and also give a pointer to a list archival site so that
they can catch up on any postings they might have missed.
If you want to get the ball rolling about this, toss an
email to webguy@thea... asking them to adjust
the netfilter list archives they have to suck things in
from the new lists at vger.
Then you can use the marc.info URL as an archive location.
Or you can continue to archive at netfilter.org if you
like and point people there.