Thank for info's.
My mail server works on Lotus Domino, and there is a option "DNS Backlist Filters" which checks mail sender server address on sites "relays.ordb.org; bl.spamcop.net" and reject mail if found there. But when I start using avast as mail relay, my mail server see that all incoming messages comes from 127.0.0.1 address /localhost/ and accept it.