Numbering nameservers and resolvers

Jared Mauch jared at
Tue Aug 17 12:52:20 UTC 2010


On Aug 17, 2010, at 8:11 AM, Sven Olaf Kamphuis wrote:

> this whole "you have to put 2 nameservers on two seperate subnets at two different locations" seems a bit.. pre-1993 to me.
> plus, why only 2, why not... 20 or so, all in different parts of the world and let bgp handle the rest.

There's an important component that is missing from the above.  It's one thing to have a single nameserver hosted in such a manner, but through operational integration and history there are still a lot of domain names that are not fault tolerant.

I remember "in recent years" a ccTLD that ended up without functioning services as a result of poor nameserver site selection.

Ideally you would have a system with two geographically diverse nameservers for a domain, under seperate (routing) administrative control.

One of my former employers backhauled all their legacy nameservers to a single site, eg: e[0-2]

While they were originally on diverse subnets and geographical locations, this appears to have changed.

Selecting a site outside of your control is valuable.  When I was hostmaster at, we "traded" with  These days, if I were in the same role, I would want to have three instead of two.  Asia, Europe and US someplace.  If US only, east, west and central.

If you look at, our "off-net" resolver is

This means if there is a ntt meltdown, there's a good chance you can still resolve related names off-net.

- Jared

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