Hi all,
I have the following config smtpd_client_restrictions = but still get warnings like this postfix/smtpd[24986]: warning: hostname server17-ams1.internet-census.org does not resolve to address 107.6.163.34: Name or service not known My understanding is that there should be no warning because the issue is explicitly checked by the "reject_unknown_client_hostname" directive. Am I missing something? Is it possible to eliminate this warning? Thanks |
Eugene Podshivalov:
> Hi all, > I have the following config > > > smtpd_client_restrictions = > > reject_unknown_client_hostname > > smtpd_helo_required = yes > > smtpd_helo_restrictions = > > reject_invalid_helo_hostname, > > reject_non_fqdn_helo_hostname, > > reject_unknown_helo_hostname > > smtpd_sender_restrictions = > > reject_non_fqdn_sender, > > reject_unknown_sender_domain > > > but still get warnings like this > > > postfix/smtpd[24986]: warning: hostname server17-ams1.internet-census.org > > does not resolve to address 107.6.163.34: Name or service not known > > postfix/smtpd[24986]: connect from unknown[107.6.163.34] > > postfix/smtpd[24986]: NOQUEUE: reject: CONNECT from unknown[107.6.163.34]: > > 450 4.7.25 Client host rejected: cannot find your hostname, [107.6.163.34]; > > proto=SMTP > > postfix/smtpd[24986]: disconnect from unknown[107.6.163.34] ehlo=0/1 > > quit=1 commands=1/2 Postfix logs this warning, so that you can understand WHY a client may be rejected with reject_unknown_client_hostname, and how the problem may be fixed. 1 - A problem with the address->name mapping (lookup failed) 2 - A problem with the address->name mapping (the mapping does not exist). 3 - A problem with the name->address mapping (lookup failed) 4 - A problem with the name->address mapping (the mapping does not exist) 5 - A problem with the name->address mapping (the mapping does not match the client IP address) In your case the probkem was #4. Wietse |
Thanks for the reply. The warning says that "hostname does not resolve to address" (case #4) but then the log says that connection is rejected because it cannot find a hostname (case #2). So which one is the actual rejection reason? Doesn't it feel a bit confusing? Regards пн, 23 нояб. 2020 г. в 17:40, Wietse Venema <[hidden email]>: Eugene Podshivalov: |
> postfix/smtpd[24986]: warning: hostname server17-ams1.internet-census.org
> does not resolve to address 107.6.163.34: Name or service not known This is a type 4 error (the name->address mapping does not exist). > postfix/smtpd[24986]: connect from unknown[107.6.163.34] > postfix/smtpd[24986]: NOQUEUE: reject: CONNECT from unknown[107.6.163.34]: > 450 4.7.25 Client host rejected: cannot find your hostname, 107.6.163.34]; Postfix was unable to determine the remote SMTP client hostname. This error message is sent to the remote SMTP client. Error details are not made available to the remote SMTP client. Error details are logged only. Then, the local system administrator can deal with it. Wietse |
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