SMTP<< 450 4.7.1 Client host rejected: cannot find your reverse hostname.

[andy75180]

Hi ya,

I have this really annoying problem with my Exim server.

99% of my emails get delivered correctly, but sometimes I get a bounce back with the error: SMTP<< 450 4.7.1 Client host rejected: cannot find your reverse hostname

All my reverse rDNS entries are correct and resolve to my hostname correctly. So I don't understand why this happens now and again.

Any help anybody?

Andy

[thewebhosting]

Kindly provide us the mail logs for the bounce back mail which you are receiving. You can check the mail logs from the below location:

/var/log/exim_mainlog

[andy75180]

2009-08-30 22:51:04 cwd=/usr/local/cpanel/whostmgr/docroot 2 args: /usr/sbin/exim -bpc
2009-08-30 22:51:04 cwd=/usr/local/cpanel/whostmgr/docroot 2 args: /usr/sbin/exim -bp
2009-08-30 22:51:06 cwd=/usr/local/cpanel/whostmgr/docroot 3 args: /usr/sbin/exim -Mt 1MhpPJ-0004k8-W9
2009-08-30 22:51:06 cwd=/usr/local/cpanel/whostmgr/docroot 4 args: /usr/sbin/exim -v -M 1MhpPJ-0004k8-W9
2009-08-30 22:51:08 1MhpPJ-0004k8-W9 SMTP error from remote mail server after RCPT TO:<xxxxx@xxxxx>: host emdch-mx11.nt.gov.au [203.26.75.14]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [115.124.105.87]
2009-08-30 22:51:10 1MhpPJ-0004k8-W9 == xxxxx@xxxxx R=dk_lookuphost T=dk_remote_smtp defer (-44): SMTP error from remote mail server after RCPT TO:<xxxxx@xxxxx>: host emdch-mx21.nt.gov.au [203.26.75.16]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [115.124.105.87]
2009-08-30 22:51:13 cwd=/usr/local/cpanel/whostmgr/docroot 2 args: /usr/sbin/exim -bpc
2009-08-30 22:51:13 cwd=/usr/local/cpanel/whostmgr/docroot 2 args: /usr/sbin/exim -bp
2009-08-30 22:51:27 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc

[thewebhosting]

Make sure that you have setup PTR record for your server, since some mail service provider requires it to send/receive emails.