Weird thing happening everything 3-4 weeks...

[Ugo Bellavance]

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>
> My first thought is DNS. It only makes sense. But the problem is, I can't
> figure out what.
>
> The mailgateway server is using our ISP's DNS servers, which are setup in
> /etc/resolv.conf. My thinking is that something is going on with our ISP's
> DNS servers. What, I don't know, but it is consistent and happens every 3-4
> weeks.
>
> The only other thing that I can think of is that we have a private BIND
> server that acts as a caching-nameserver for our clients as well as serving
> up private web pages. But I don't see that being the problem.
>
> Anyone have any ideas? It's not a big problem. It is more of a nuissance.

For sure you should have a caching nameserver installed locally or nscd.
  At least for bandwidth saving and processing saving for your ISP's DNS
server.  And if this is the cause, you'll know within a month.

What top iostat and vmstat say when the delays are high?

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