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Re: How to block a MX without revers DNS is working ?

From: Alexander Grüner (agruenergmx.de)
Date: Tue Jul 04 2006 - 01:58:05 CDT

> What about this restriction in postfix v2.3
> reject_unknown_reverse_client_hostname
>
>
http://www.postfix.org/postconf.5.html#reject_unknown_reverse_client_hostname

Hi John :-)

Quote: "This is a weaker restriction than the
reject_unknown_client_hostname feature, which requires not only that the
address->name and name->address mappings exist, but also that the two
mappings reproduce the client IP address."

As far as I understand, it works only for clients which have just an IP
address wihtout any FQDN. Like this one in my log: 59.12.196.86

host 59.12.196.86
Host 86.196.12.59.in-addr.arpa not found: 2(SERVFAIL)

Do we have 2 cases here ?

1. Just IP, no FQDN at all (example 59.12.196.86)
2. IP -> FQDN works, but revers DNS does not (example 71.15.125.33)

Regards,
Alexander