Today i made a relay test with telnet mail-relay.mail-abuse.org and i got following log!
:Relay test: #Test 10
>>> mail from:
<<< 250 Sender accepted.
>>> rcpt to: <"nobody@mail-abuse.org">
<<< 553 Sorry, that domain isn't in my list of allowed rcpthosts.
>>> rset
<<< 250 OK
:Relay test: #Test 11
>>> mail from:
<<< 250 Sender accepted.
>>> rcpt to: <"nobody%mail-abuse.org">
<<< 250 Recipient accepted.
>>> QUIT
<<< 221 Good bye.
How can i deny this relay?