sendmail header removal

Oliver Falk oliver at
Tue Jan 5 16:19:06 GMT 2010

Am 05.01.2010 16:53, schrieb Steven Andrews:
> I’ve got a couple sendmail/mailscanner boxes that we use to front end
> our exchange boxes inbound and outbound. We’ve run into a problem with
> any email going to’s clients as they do a deep header
> analysis and find private IPs in the headers and then the block based on
> that.
[ ...]
 > So, what I’d like to do is find a way to rip out the private IPs of the
> message headers when we send them, or massage them into public IPs. Is
> there any way to do this with sendmail?

I had a similar problem (I believe it was some Barracuda Spam Firewall) 
months ago.

What helped in the end was to hide the client IP on my SMTP (SM/MS). Try 
adding this (or similar) to the and rebuild your

dnl #
dnl # Hide client IP
define(`confRECEIVED_HEADER',`by $j $?r with $r$. id $i; $b')dnl

Well... If it is the received header which is your problem.

Please note: Under some circumstances this *could* cause your troubles 
when trying to debug other kind of mail delivery problems; however none 
come to my mind immediately. :-)


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