One thing to keep in mind is the dns lookup on a host is part of the
transactional process, and inclusive of total delay.
I've seen everything from crappy/slow dns servers causing application
latency across clusters to broken dns records causing a good 10second
delay in responding to clients due to dns. That is part of the reason
developers will hard code things I've found, working around bad
infrastructure, sometimes even the dns server's at fault.
Using remote dns (not local lan), consider that takes you from
microseconds of latency to potentially hundreds of milliseconds remote.
This is another reason to have local caching servers, or even at times
local to the hosts as well with something like dnsmasq. When dealing
with applications that make dns queries as part of their logic tend to
dislike remote resources. With distributed applications and/or latency
sensitive apps, can cause real performance issues.
Another thing - consider the cost of the dns traffic in bandwidth
hosting it somewhere. Watching things like netflow at local dns shop
was interesting to see just how much dns traffic really does get
generated, both from servers, clients, and everyone else in between
local lan or internet. Even running dns services for a popular domain
on a dedicated hosting bandwidth allowance, I've seen blow out usage
thresholds, just in overhead of udp/53 traffic @~64bytes or smaller
packets. Probably a poor application too, seen .net code go crazy
spewing dns requests at crippling rates of requests when not explicitly
disabling lookups as part of a socket response method.
Side note:
I never realized dnsmasq is as versatile as it is, but using it with my
little ddwrt box, it does nice things with automagically mapping dhcp to
forward/reverse dns records with a little config grease. It's been good
enough that I retired my bind servers for a more compact/embedded
solution just on the router itself. Might be worth looking into.
-mb
On 10/05/2015 12:35 PM, Keith Smith wrote:
>
> Thank you Stephen and Michael!!
>
> Sense I am running a server connected to Cox, is there any advantage
> of using Cox's DNS servers?
>
> Thanks!!
>
> Keith
>
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