[Flounder] DNS Caching Server

[Russell Coker]

On Monday, 30 May 2022 20:30:06 AEST DL Neil via Flounder wrote:
> Unfortunately, in this situation (low volume user of the DNSWL, thus
> $free access, but limited by number of DNS-queries per 24-hrs), the
> problem of using a DNS Service (or the service-provider's) is that
> others will also contribute to the query-limit.
> 
> Sure-enough, reports were returning rejected calls. Accordingly, being
> the only/single IP-source of all queries has put the WL to work,
> successfully.

OK, that's a good point.  So it's not inherently a SpamAssassin issue, but an 
issue of a DNSBL service that SA uses.

> > https://doc.coker.com.au/papers/benchmarking-mail-relays-and-forwarders/
> > https://etbe.coker.com.au/2021/05/03/dns-lots-ips-postal/
> > 
> > In 2006 I presented a paper on benchmarking mail relays and forwarders
> > which surprisingly showed that BIND as a name server was a major
> > bottleneck.  At the time I didn't investigate any other DNS caches as the

> This is surprisingly helpful. Whilst not quite in the 2006 category, the
> VPS' config is becoming 'old':
> 
> CentOS 7.9
> SpamAssassin x86_64 3.4.0 (CentOS 6.el7 release)
> Postfix 2.10.1
> unbound 1.6.6

CentOS 7 was released in 2014, so it is quite old.  But it shouldn't miss any 
performance features in modern CPUs that matter for mail delivery.

> inxi reports that it is running well within (<80%) its parameters, but
> it is small.
> 
> I'm not going to uninstall unbound and install bind to perform a
> comparison, but you can see why I was shying-away from something rumored
> to be resource-hungry.

https://www.linode.com/pricing/

Currently the cheapest VM on Linode (which I have found to be a reliable 
hosting company) has 4G of RAM and SSD storage.  My current mail server is a 
VM with 10G of RAM mainly because of the PHP stuff and database servers 
running as well as having slow storage so needing more RAM for cache.  The 
email and web services related to it could fit in the minimal Linode VM 
easily.  Email just isn't a big thing by the standards of today's servers.

But when running such an old server changing software to test isn't worth 
doing.

-- 
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