No-spam email are ok for the ISPConfig spamfilter,but not for the receiver spamfilter

[voltron81]

Hello to everybody.
I've realized a mailserver based on ISPConfig and debian.
It's working just fine.

I've just one problem: sometimes happen that somebody try to send me an email from a ISP that is NATing the IPs; the ISPConfig spamfilter is of course checking that email and mark is as NOT spam.
So the email is passed to the receiver, that is using a local spamfilter.
Well, this spamfilter is marking that email as SPAM.

This is the scenario:

LocationA _____ LocationB ___________ LocationC
the sender_____ISPConfig server _______ receiver


Doing an mxtoolbox blacklist check, the IP of the sender(that in reality is of his ISP, because it's NATing all his customers to few IP) is blacklisted...
For the moment I just remove that IP from the blacklist and I solve the problem.
But unfortunately this problem is happening quite often.

So my question is: there is a way to setup the ISPConfig to just avoid the IP of the sender when is passing the email to the receiver, so that the spamfilter on the locationC will not mark that email as spam?

Or do you have another idea to solve this problem?

Thanks
Michele

[till]

To me it seems to be more a problem of the spamfilter on the local system and not the filter in ispconfig as the ispconfig filter acts correctly. The filter on the local system should ignore these ip addresses and only use the real sender IP and not any IP addresses that the mail passed on the way to the receiver. As you run already a spamfilter on the ispconfig system, you should remove the filter on the local system.

[voltron81]

Hi Till.
I totally agree with you.
But unfortunately I've no access at all to the receiver spamfilter.
I know that is not a problem of ISPConfig. But I've access just to the ISPConfig server.
That's why I want to find a way to setup ISPConfig server to avoid the sender IP when deliver the email to the receiver.

Or maybe do you have a better idea?

The filter on the local system should ignore these ip addresses and only use the real sender IP and not any IP addresses that the mail passed on the way to the receiver.

It's using the real sender IP, that is a bad IP (because the ISP is NATing all the users with few IPs)


thanks
Michele

[till]

I think your problem is not realted to the spamfilter or ispconfig as these mail headers are not changed by amavisd. I think the only possible solution might be to use postfix header filters to delete or replace header lines that conatin IP addresses from private networks like 192.168.*

A header check like this might work:

/^Received:.*\[(192\.168|172\.(1[6-9]|2[0-9]|3[01])|10)\./ IGNORE
/^Received:.*\[127\.0\.0\.1/ IGNORE

See also here:

http://marc.info/?l=postfix-users&m=122106353826539&w=2

[voltron81]

Thanks a lot Till.

I'll have a look to that link...

Cheers
Michele