Re: mail headers - why do they differ?

[Sam Varghese <sam@gnubies.com>]

On Sat, Oct 13, 2001 at 01:13:43AM +0200, Carel Fellinger wrote:
> It's very easy to forge From-addresses in email, that's what the line
> 
>    Sender = "Sam Varghese <sam@gnubies.com>"
> 
> in your ~/.muttrc files tell mutt to do. Most MUA (mail user agents)
> allow such things. But fortunately most sane MTA (mail transport
> agents) fix this by adding a true Sender header.  This seems a catch
> 42, but Linux wouldn't be unix if there wasn't a way out:)  Either add
> the user samuel to Exim's trusted users list (which would allow samuel
> to forge the From header amongst other things, so NOT recommended) or
> use Exim's powerfull header rewriting trickery or login as sam.
> 
> I prefer to rewrite headers in such cases, look at the section
> "Address rewriting" in Exim's info files.  The trouble with older
> exim's (the one in potato) is that the rewriting is a global thing.
> Newer exim's allow to specify rewriting rules per transport.  You can
> easily fake your own special cased rewriting rules per transport for
> older versions by having the transport go through a pipe, and in that
> pipe have a sed call to do the tranformations you need.

I've noticed that about the version of exim that comes with potato.
I have potato on both my workstation and my server - I can't afford
to do a dist-upgrade over the web as I pay by the meg for my web/mail.

> > True, I log in to my workstation as samuel - should I
> > change this to sam? ..................................
> 
> no, why should you?
> 
> > ................... And would it suffice to change the
> > username in /etc/passwd and /etc/shadow and then reboot?
> 
> you should fix /etc/group and /etc/sgroup too.  And forget about
> rebooting, just login afresh if that makes you feel better.

I've changed the login but find that I don't have an /etc/sgroup file.

Thanks for the reply.

Sam
-- 
(Sam Varghese)
http://www.gnubies.com