Re: Localized mail servers, global scope

[Joe Abley <jabley () isc org>]

On 2005-06-23, at 10:57, Suresh Ramasubramanian wrote:

> Wild idea and there's just too much good german beer here at MAAWG
> (www.maawg.org) in Dusseldorf, but .. anybody tried anycasting a
> mailserver?
>
> Operationally that is ...

I know of people who have anycasted the address used by their clients  
for mail submission using SMTP (so that clients connect to a stable  
address, and the node which services their request varies according  
to where they are connecting from).

Like all applications of service distribution using anycast, care is  
required: e.g. a stable, internal network with a well-known topology,  
and anycast nodes placed such that node selection by clients is  
consistent, packet-to-packet, for periods of time far exceeding the  
expected maximum transaction time.

The places I have seen this done have had POPs connected with  
expensive and congested links, so keeping mail submission from  
customers local and snappy was a big win.

I think you're talking about anycasting a server across the Internet  
to act as a low-numbered MX, though. I haven't met anybody who  
thought that was a good idea, yet. :-)


Joe