OK, I found http://www.postfix.org/postconf.5.html#smtpd_client_connection_count_limit
The default value is 50. So it seems no need to modify anything after reading Noel Jones's analyzation. Thanks. ---- On 星期五, 21 十月 2016 11:51:50 -0700Noel Jones <[email protected]> wrote ---- On 10/21/2016 1:13 PM, vod vos wrote: > Hi guys, > > When I reviewed the mail.log, it showed a IP was trying to test if > relay was open or not. However, the times were too many. > > * > What is the max limited times of postfix defaultly defined? > See the STRESS_README document. http://www.postfix.org/STRESS_README.html > > * > And how to modify it or how to set helo/ehlo restriction? > > > Thanks. > > Here is the log: Many unrelated entries snipped. > > Oct 19 22:21:34 mail postfix/smtpd[1796]: connect from > unknown[61.145.214.178] client connects. > Oct 19 22:21:42 mail postfix/smtpd[1796]: NOQUEUE: reject: RCPT from > unknown[61.145.214.178]: 554 5.7.1 <[email protected]>: > Relay access denied; from=<[email protected]> > to=<[email protected]> proto=ESMTP helo=<XL-20160621FCVQ> Client attempts unauthorized relay, postfix rejects it. > > > Oct 19 22:21:42 mail postfix/smtpd[1796]: NOQUEUE: reject: RCPT from > unknown[61.145.214.178]: 554 5.7.1 <[email protected]>: > Relay access denied; from=<[email protected]> > to=<[email protected]> proto=ESMTP helo=<XL-20160621FCVQ> (other Relay attempts snipped) > > Oct 19 22:22:05 mail postfix/smtpd[1796]: improper command > pipelining after DATA from unknown[61.145.214.178]: client talks out of turn, then tries some more unauthorized relays. ... > Oct 19 22:22:29 mail postfix/smtpd[1796]: too many errors after DATA from unknown[61.145.214.178] postfix hangs up on the bad client. > > > Oct 19 22:22:29 mail postfix/smtpd[1796]: disconnect from unknown[61.145.214.178] ehlo=1 mail=10 rcpt=0/10 data=0/10 rset=10 commands=21/41 Client tried 10 recipients, 0 were accepted; all were unauthorized relay attempts. After the 10th attempt, postfix disconnected. Looks as if postfix is working just fine. Nothing more to do here. -- Noel Jones
