[stunnel-users] Re: Adding header to SMTP msgs

Michal Trojnara Michal.Trojnara at mobi-com.net
Sat Nov 25 21:28:47 CET 2006

On Saturday 25 November 2006 20:24, Eric B. wrote:
> Would it be very difficult to update stunnel and make it a
> configurable option to insert the originating IP as a header in the mail?
> ex: something like X-st-originating-IP:  or something like that.

Since adding a header to each email address within a connection requires 
building SMTP parser - I could say it's very difficult. Probably a wealthy 
sponsor could make me change my mind, but otherwise such change obviously 
breaks the KISS principle that stunnel is based on.

> Am actually using an anti-spam proxy in front my my SMTP server which
> doesn't have native SSL support (ASSP).  And if I use the SMTP server's SSL
> support, I'll completely be bypassing the AntiSpam proxy which will
> completely defeat the purpose of anti-spam.

What about installing an SMTP router in front with RBL support, than your 
anti-spam proxy, than another instance of SMTP server for local delivery?
For sure it's easier than adding another feature to stunnel.
I use a similar configuration for antivirus scanner based on Postfix.

> >Are there really a lot of spammers that use SSL to send spam?
> Actually, yes.  There are a significant number of spammers that use SSL
> mainly b/c a lot of systems don't check SSL ports against spam, etc.  It is
> becoming more and more prevalent.  I woudl have to say that at least 50-60%
> of the spam comes via the SSL port.

I didn't know that.  Thank you.

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