[SOLVED] Re: My post mail server is used for spam
2011/11/15 Stan Hoeppner <stan@hardwarefreak.com>:
> On 11/15/2011 5:44 AM, Olivier BATARD wrote:
>> Thanks for the answer, when I run a grep -e "connect from" on the
>> syslog I got this :
>>
>> Nov 15 12:32:47 VOLTALIAMSG postfix/smtpd[31110]: disconnect from
>> unknown[192.168.150.254]
>> Nov 15 12:32:49 VOLTALIAMSG postfix/smtpd[31102]: connect from
>> unknown[192.168.150.254]
>> Nov 15 12:32:53 VOLTALIAMSG postfix/smtpd[31129]: disconnect from
>> unknown[192.168.150.254]
>> Nov 15 12:32:56 VOLTALIAMSG postfix/smtpd[31110]: connect from
>> unknown[192.168.150.254]
>
> No modern NAT/PAT router should ever replace the source address. If a
> firmware upgrade doesn't fix this problem, chuck that router as quick as
> you can and get a new one.
>
>> the 192.168.150.254 is my router. Seems that postfix consider it like
>> a internal host.
>
> Of course Postfix does. Because it *is* an "internal" host:
>
> mynetworks = 192.168.150.0/24 ...
>
>> Anyway we have a router which uses NAT to forward smtp data to our
>> server. How can we configure postfix and router to send mail only from
>> my domain and not sending and accepting spam ?
>
> If you do not have users submitting mail for relay from the public
> internet (i.e. roaming laptop users "outside" the router), simply
> rejecting smtp connections from the router's private IP address will
> solve the problem. Edit main.cf with the modification below and do a
> "postfix reload":
>
> mynetworks = !192.168.150.254 192.168.150.0/24
>
> The "!" excludes the address.
Thanks that solve my problem
>
> If you do not actually have a working IPv6 network, remove the IPv6 junk
> from mynetworks. If you don't have webmail running on the Postfix box,
> nor programs that need to inject mail into Postfix, remove the loopback
> address from mynetworks as well.
Thanks for the advice.
>
> P.S. I'm shocked you still have a NAT/PAT router in 2011 that rewrites
> source addresses. Treat that thing like hot plutonium--replace it ASAP.
>
Yeah I was quite shocked too, so we'll replace soon as soon as the
client sign the bill :)
Anyway thanks a lot.
Olivier
> --
> Stan
>
>
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