[Mailman-Developers] Re: To VERP or not to VERP?

J C Lawrence claw@kanga.nu
Sun, 17 Jun 2001 21:59:08 -0700

On Sun, 17 Jun 2001 14:23:32 -0700 
Chuq Von Rospach <chuqui@plaidworks.com> wrote:

> This isn't a discussion-list system, but the delivery setup could
> be adapted to that fairly easily. If you were going to do
> something similar on Mailman, you could do it by having a farm of
> SMTP outgoing machines under a round-robin with a short time-out,
> and making sure qrunner re-looks up the IP after every message. Do
> that, and then extend to allow for parallel qrunners, and you can
> buidl a heck of a mail list farm. 2.1 will do most of that fairly
> easily, the rest is figuring out and configuring the SMTP smurf
> farm and its round-robin.

Its arguably cheaper/easier to instead us a load balancer box as the
SMTP target which then does a per-transaction round-robin to the
target nodes in the farm.  Fairly easy to do, just a little proxy,
and then let rip.  Mailman never knows any different, you've got
management abstraction in the proxy box, and can add, remove, and
fail out nodes transparently without any cacheing problems torquing
the queues.

> The downside is you add administrative complexity, plus you need
> to engineer getting the data where it needs to be (and the
> security of making sure nobody else uses your smurfs...). 

Sit the smurf farm behind a router that redirects all inbound port
25 connections to <where-ever>.  At that point the only access to
the smurfs is from the inside via your proxy box as above.  

J C Lawrence                                       claw@kanga.nu
---------(*)                          http://www.kanga.nu/~claw/
The pressure to survive and rhetoric may make strange bedfellows