3.
Main cause of mailman problems is IMHO the following router
configuration, which I use because all outgoing mail is being received
by internal mailserver running old version of sendmail (hp-bv.nembv.cz)
which is not visible on the Internet, and then forwarded to exim
(bsdbv.nembv.cz). In order do decide whether mail should be forwarded to
hp-bv.nembv.cz or our ISP's gateway vitis.bv.anet.cz I use route_list,
which seems to cause headache to mailman... this is the config: