On 29.04.21 06:25, Fourhundred Thecat wrote:
Postfix does not show hostname for a connecting IP address, when the
hostname does not have reverse lookup:
Example from my log:
warning: hostname zg-0416b-243.stretchoid.com does not resolve to
address 192.241.220.141: Name or service not known
connect from unknown[192.241.220.141]
timeout after EHLO from unknown[192.241.220.141]
disconnect from unknown[192.241.220.141] ehlo=1 commands=1
It is a good thing that postfix warns me that hostname does not resolve
back to the IP, but why does it show:
connect from unknown[192.241.220.141]
instead of
connect from zg-0416b-243.stretchoid.com[192.241.220.141]
The IP has DNS record, so even when reverse does not work, I would like
to see the hostname that is connecting
can this be configured?
On 2021-04-29 10:25, Matus UHLAR - fantomas wrote:
no. There's no poing in trusting reverse lookup if it's not
forward-confirmed.
Anyone can poing their reverse DNS to any domain they don't own.
On 29.04.21 14:04, Fourhundred Thecat wrote:
when I query the IP with "host" command, I get:
$ host 192.241.220.141
141.220.241.192.in-addr.arpa domain name pointer
zg-0416b-243.stretchoid.com.
same when I do it in my python script using gethostbyaddr()
Can't postfix be configured to do it similarly ?
Once again:
The result of reverse resolution will NOT be used, unless it's verified by
forward resolution.
Anyone can point their reverse DNS to any hostname and you should NOT use it, if
the hostname does not map back to that IP address.
it will be logged, but that's all.
Get proper reverse/forward name, possibly not generic.
what do you mean? I don't control these IP addresses.
These are just connecting to my mail server
you can turn off referse lookup if it annoys you.
Nobody serious will use random unconfirmed reverse hostnames.
--
Matus UHLAR - fantomas, [email protected] ; http://www.fantomas.sk/
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