[SLUG] DNS glue means?

["Sonia Hamilton" <sonia@xxxxxxxxxxxx>]

I'm trying to understand what 'glue records' are for in DNS. I've googled
and think I've worked it out, but I haven't come across a good definition
yet.

If I *only* have:
> foo.com. NS ns1.bar.net.
> foo.com. NS ns2.qux.net.
this is a 'glueless' domain, isn't it?

Whereas if I have:
> foo.com. NS ns1.foo.com.
> foo.com. NS ns2.foo.com.
> ns1.foo.com. A 1.2.3.4
> ns2.foo.com. A 5.6.7.8

The last two A records are 'glue' records, and the domain isn't 'glueless'.

For what I can understand, the latter is more reliable, as when someone
queries .com. for foo.com., the .com. server can provide the address
without any additional queries. Whereas for the glueless case, .net. would
need to be queried to find out information about bar.net. or qux.net; when
you get glueless built on glueless built on glueless etc things start to
slow down and/or fail.

Is this correct?

--
Sonia Hamilton
Linux - Free as in 'Free Speech', not 'Free Beer'