[Mailman-Users] Hide Senders IP-Adress (not Email-Adress) when sending mail to list

Hi,

I am trying to find a solution for filtering the first-senders ip/host information out of an email header. (I am running mailman with postfix).

I am already doing the anonymization when sending mail for "normal" users by setting smtpd_sasl_authenticated_header=yes and then using header_checks to replace the part of the header where the users ip address can be found with 127.0.0.1.

For mailman I found the anonymous list option, that will hide the email-address of the original sender but not his ip address. What I want to do is leaving the senders email-address in the header but hide the ip-address (or replace it by the list servers address).

[The reason for this (in case this raises questions) are the data retention efforts of germany and other countries.]

So my questions would be:

• Is there a possibility for mailman itself to replace the senders address by lets say the mailservers address (IP not Mail).

• If not, is there a possibility to add any extra header information (like the Authenticated-Header i mentioned before) by mailman? I would need some unique string inside the header that can be addressed by my rexular expression.

Thanks in advance, Sven.