[BlueOnyx:01263] Re: SMTP Relay servers

[Colin Jack]

Thanks Thomas - I will take a look.

Colin

> -----Original Message-----
> From: blueonyx-bounces at blueonyx.it [mailto:blueonyx-bounces at blueonyx.it] On
> Behalf Of Thomas Andreassen
> Sent: Tuesday, May 19, 2009 3:06 PM
> To: BlueOnyx General Mailing List
> Subject: [BlueOnyx:01261] Re: SMTP Relay servers
> 
> VRRP will solve the issue about DNS, but load balancing with nat is easy and nice to
> setup (try mikrotik)
> 
> Thomas
> 
> -----Opprinnelig melding-----
> Fra: blueonyx-bounces at blueonyx.it [mailto:blueonyx-bounces at blueonyx.it] På
> vegne av Colin Jack
> Sendt: 19. mai 2009 15:48
> Til: cobaltfacts at virtbiz.com; BlueOnyx General Mailing List
> Emne: [BlueOnyx:01257] Re: SMTP Relay servers
> 
> 
> > Realistically, the idea is a non-starter.  The problem you will run into
> > is that the end-user's ISP will cache a lookup.  Then of course the
> > client machine will do a lookup and resolve the hostname to the IP.
> > Then it will cache.
> >
> > Then if one of your SMTP boxes dies for some reason, anybody who had
> > already been using that would be down, but the other customers that
> > achieved the lookup to another box would still ostensibly go through.
> >
> > Sure, you could monkey with TTL's and expires, but then you're creating
> > more overhead on your end with all the lookups, and there's the added
> > issue that in order to reduce network load many of the larger ISPs
> > completely ignore your TTL and expire times and cache for whatever time
> > period they see fit.   This appears to be an increasing trend.
> >
> > The better idea is just to have your SMTP not "go down", and if you're
> > really concerned, or you have a history of flaky SMTP boxes, have a
> > warm-spare standing by.
> >
> > Alternatively, you could set up some fancy NAT-based load balancing at
> > your server-side.
> >
> > But DNS is not an ideal way to handle this.
> >
> > --
> > Chris Gebhardt
> > VIRTBIZ Internet Services
> 
> Cheers Chris - that was my gut feeling I suppose - just hoped somebody had a
> clever idea!
> 
> We don't have a history of SMTP boxes failing (touch wood) but sometimes they can
> get busy with a spam storm or suchlike, so it was just an idea.
> Also in the event that it does go down it gives us some breathing space.
> 
> Ho hum
> 
> Colin
> 
> 
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