What is a nameserver — and why you need at least two

An authoritative nameserver is the machine that holds the actual answer for your domain. When someone opens your site, their resolver eventually asks one of YOUR nameservers "what is the address of example.com?" — and the answer it gives is final. Not a cache, not an opinion: the source.

You can see which nameservers answer for any domain:

dig example.com NS +short

Why at least two

If your only nameserver goes down, your domain does not get slow — it disappears. Every service under it (site, e-mail, APIs) stops resolving as caches expire. RFC 2182 recommends at least two nameservers, on distinct networks, precisely because a nameserver outage is a full-domain outage.

The catch: two nameservers in the same network (same /24 prefix, same datacenter) satisfy the count and fail together. The redundancy that matters is network diversity — two answers from two places that do not share a failure.

What breaks when this is ignored

• One nameserver only: any maintenance window becomes a domain outage.
• All nameservers in one network: a single routing incident takes down everything at once.
• Nameservers that answer differently: intermittent, maddening bugs — resolvers pick one at random.