[Mailman-Users] Spam filtering

[Larry Stone]

On 2/17/10 7:56 AM, Geoff Shang at geoff at QuiteLikely.com wrote:

> 1.  It's possible to use an IP address to block(at least temporarily)
> these messages.  If I put this IP address into a Mailman spam filter, will
> this be checked *before* checking whether or not the person is a member of
> the list?  I want to know if list admins can block these without bugging
> their site admins to do it upstream.

Probably better to do this in the MTA, not Mailman.

> 2.  One idea I came up with for rejecting spoofed mail is for the
> receiving SMTP server to somehow check if the sending one is an MX for the
> domain given in the From header.  Are there any obvious problems with this
> approach?  Is anyone actually doing this?  It seems so simple that there
> surely must be some reason why it's not done.

A bad idea. MX records identify servers that RECEIVE mail for the domain.
They say nothing about which servers can SEND mail for the domain. While in
many cases, they are the same servers, there is no requirement that they be
so and many large ISPs split the functions.

-- 
Larry Stone
lstone19 at stonejongleux.com
http://www.stonejongleux.com/