postmaster@ wird sicher gehen.
Wohl nicht immer wie dieser Report von dsbl.org wegen GMX zeigt:
2003/May/12 19:09:33 UTC Removal Confirmation Refused EMail address: postmaster@mail.gmx.net Requestor IP: 80.121.15.240 Message Report: Connected to 213.165.64.20 but sender was rejected. Remote host said: 553 {mp012-rz3} Only registrated user are allowed to use this system