did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4

Boa noite,

estou tendo muitos logs com a mensagem: did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
utilizo sendmail, tudo funciona perfeitamente, porém são muitas essas mensagens, todas vindas de ips com reversos, dial, virtual, vivozap, dsl, etc..
segue um trecho do log abaixo:
alguma idéia?





Aug 6 19:27:30 mail sm-mta[7417]: p76MROlJ007417: badfa405.virtua.com.br [186.223.164.5] (may be forged) did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:31 mail sm-mta[7406]: p76MROta007406: ip-187-91-95-29.user.vivozap.com.br [187.91.95.29] (may be forged) did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:31 mail sm-mta[7408]: p76MRP09007408: 187-57-105-67.dsl.telesp.net.br [187.57.105.67] (may be forged) did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:32 mail sm-mta[7432]: p76MRWOI007432: 187-85-152-71.gegnet.com.br [187.85.152.71] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:32 mail sm-mta[7409]: p76MRRfv007409: 201-24-142-49.gnace702.dsl.brasiltelecom.net.br [201.24.142.49] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:34 mail sm-mta[7416]: p76MRS0n007416: 187.114.225.159.dynamic.adsl.gvt.net.br [187.114.225.159] (may be forged) did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:34 mail sm-mta[7410]: p76MRQgf007410: 189-78-23-104.dsl.telesp.net.br [189.78.23.104] (may be forged) did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:35 mail sm-mta[7411]: p76MRRSx007411: 84.121.182.28.dyn.user.ono.com [84.121.182.28] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
Aug 6 19:27:36 mail sm-mta[7415]: p76MRSXf007415: ppp-94-68-145-65.home.otenet.gr [94.68.145.65] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA-v4
^C