I am using a Centos 6.5 machine as a mail server with sendmail as the MTA. I have a problem with a delay of sendmail presenting its banner so that the process of accepting e-mail can begin. The log files demonstrate as much as a 2 minute delay between the connection and the banner presentation. #telnet Mail.DOMAIN.com 25 Connected to mail. Escape character is '^]'. < two minute delay before the next line is presented> h220 Mail.DOMAIN.com. ESMTP Sendmail 8.14.4/8.14.4; Sun, 23 Mar 2014 10:17:44 -0500 Log entries on the mail server for the above connection: Mar 23 10:16:05 Mail sendmail[31229]: NOQUEUE: connect from NAME.DOMAIN.com [10.0.0.187] Mar 23 10:17:44 Mail sendmail[31229]: AUTH: available mech=GSSAPI CRAM-MD5 DIGEST-MD5, allowed mech=EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN I have made the observation that if I put in the following line in the access file the 2 min delay goes away Connect:10.0.0.187 RELAY Obviously I can not set up a relay for every ip address, but this does solve the problem for internal network delivery of mail to the mail server. I am using named for local dns service and have not been able to identify any errors or problems. When I evaluate nslookup NAME.DOMAIN.com 127.0.0.1 I appropriately get 10.0.0.187 So far I am stumped on this problem, if any of you have suggestions I would appreciate your help Greg Ennis
This is probably being caused by DNS timeout trying to reverse-lookup the connecting IP. Check that your resolver (/etc/resolv.conf) is set correctly and responding to e.g. "dig -x [IP-address]" queries in a timely manner. If you are using DHCP, note that /etc/resolv.conf may be automatically created by the network setup scripts so manual edits may not "stick". On Sun, Mar 23, 2014 at 8:39 AM, Gregory P. Ennis <PoMec at pomec.net> wrote:> I am using a Centos 6.5 machine as a mail server with sendmail as the > MTA. I have a problem with a delay of sendmail presenting its banner so > that the process of accepting e-mail can begin. The log files > demonstrate as much as a 2 minute delay between the connection and the > banner presentation. > > #telnet Mail.DOMAIN.com 25 > Connected to mail. > Escape character is '^]'. > < two minute delay before the next line is presented> > h220 Mail.DOMAIN.com. ESMTP Sendmail 8.14.4/8.14.4; Sun, 23 Mar 2014 > 10:17:44 -0500 > > Log entries on the mail server for the above connection: > Mar 23 10:16:05 Mail sendmail[31229]: NOQUEUE: connect from > NAME.DOMAIN.com [10.0.0.187] > Mar 23 10:17:44 Mail sendmail[31229]: AUTH: available mech=GSSAPI > CRAM-MD5 DIGEST-MD5, allowed mech=EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 > LOGIN PLAIN > > I have made the observation that if I put in the following line in the > access file the 2 min delay goes away > > Connect:10.0.0.187 RELAY > > Obviously I can not set up a relay for every ip address, but this does > solve the problem for internal network delivery of mail to the mail > server. > > I am using named for local dns service and have not been able to > identify any errors or problems. > > When I evaluate > > nslookup NAME.DOMAIN.com 127.0.0.1 I appropriately get 10.0.0.187 > > So far I am stumped on this problem, if any of you have suggestions I > would appreciate your help > > Greg Ennis > > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos >
Date: Sun, 23 Mar 2014 10:39:34 -0500 I am using a Centos 6.5 machine as a mail server with sendmail as the MTA. I have a problem with a delay of sendmail presenting its banner so that the process of accepting e-mail can begin. The log files demonstrate as much as a 2 minute delay between the connection and the banner presentation. #telnet Mail.DOMAIN.com 25 Connected to mail. Escape character is '^]'. < two minute delay before the next line is presented> h220 Mail.DOMAIN.com. ESMTP Sendmail 8.14.4/8.14.4; Sun, 23 Mar 2014 10:17:44 -0500 Log entries on the mail server for the above connection: Mar 23 10:16:05 Mail sendmail[31229]: NOQUEUE: connect from NAME.DOMAIN.com [10.0.0.187] Mar 23 10:17:44 Mail sendmail[31229]: AUTH: available mech=GSSAPI CRAM-MD5 DIGEST-MD5, allowed mech=EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN I have made the observation that if I put in the following line in the access file the 2 min delay goes away Connect:10.0.0.187 RELAY Obviously I can not set up a relay for every ip address, but this does solve the problem for internal network delivery of mail to the mail server. I am using named for local dns service and have not been able to identify any errors or problems. When I evaluate nslookup NAME.DOMAIN.com 127.0.0.1 I appropriately get 10.0.0.187 So far I am stumped on this problem, if any of you have suggestions I would appreciate your help Greg Ennis --------------------------------------------------------------------------- Problem is solved.... a bit of an embarrassment ... I had two blacklisted services that were no longer active as a FEATURE in my sendmail.mc file. combined.njabl.org blackholes.mail-abuse.org Does anyone use other comparable services like these? Greg Ennis