Recommended values for a zone

Bob Harold rharolde at
Wed Jan 3 19:05:54 UTC 2018

On Wed, Jan 3, 2018 at 1:57 PM, Mik J via bind-users <
bind-users at> wrote:

> Hello,
> I would like to have your thoughts about what should be the best values
> for refresh, retry, expire and negative cache.
> In my case I have 2 DNS which are hosted in 2 different locations. These
> location are near one another (100km). The latency is very low and packet
> is 0.
> I configured a lot of zones on my DNS and they not master for someone else.
> This is a very simple setup in termes of master/slave.
> I would be tempted to
> * configure a high refresh period since I have notify configured on the
> master. What about 7200s ?
> * Configure a high retry period because I don't expect the master to be
> offline, what about 3600 ?
> * configure a expire very high like 2 days so that the DNS service would
> work even if the master is down
> * I don't have any opinion about the negative ttl yet but any advices are
> welcomed.
> What about your setups if it looks like mine ?
> Regards

I typically use an expire time of 14 days or a month.  But that said, you
need some way to get notified that zone transfers are failing.
The refresh and retry are ok, but personally I would set them lower because
they don't generate a lot of traffic, and a notify could get lost.  It
depends on how sensitive you are to extra traffic.

Negative TTL depends partly on how fast you want new (or accidentally
deleted) records to be usable.  I use 10 minutes.

Bob Harold
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