Re: [Exim] SMTP policy issues - where to take them?

Kristian Koehntopp [7/17/2003 1:38 PM] :

> Is there a mailing list that deals with SMTP policy issues, or
> are there other ressources in that direction (documents, FAQs
> and the like?). What do you recommend?
>
> I am thinking about topics like "What is better: A cluster with
> a single MX, or multiple machines with separate MXes?" "What
> trust can be put into the name that comes after a HELO
> statement? Can we demand that it resolves?" "If my secondary
> gets a mail while the primary is reachable from the secondary,
> should the secondary 4xx the incoming message?"
>
> Where would I take questions like these?

comp.mail.misc - or maybe the IETF lists.

My answers would be -

1. Depends on your network architecture - many machines with multiple
MX, or many clusters with multiple MXs gives you slightly more redundancy

2. Trust? You can't demand that a HELO resolves - but you can look for
stuff like bogus hotmail / yahoo etc helos, helos of machines that helo
as your own IP or domain, etc.

3. If your secondary gets a mail while the primary is reachable from the
secondary, there is no guarantee that the primary is reachable from
other parts of the world.