"glue" record?

[Kevin Darcy]

Not to contradict your explanation, but I think there are actually two
distinct ways in which the term "glue" is used in the DNS context. The
first is "glue record", as you have described. The second is a more gener=
ic
usage -- often expressed as just "glue" _sans_ "record" -- denoting the s=
et
of A records associated with a given set of NS records in the Authority
Section of a response (usually returned in the Additional Section of the
same response, of course). "Glue record"s (in the limited sense) are
mandated by the RFC's, but "glue" (in the generic sense) is not, except o=
f
course where a given record falls into both categories. As an example of
the two different usages, take BIND's "fetch-glue" option. This doesn't
just apply to "glue record"s as you described them, but to *all* Addition=
al
Section A records -- "glue" -- associated with the Authority Section NS
records in the nameserver's responses (in fact, named should never have t=
o
"fetch" an actual "glue record" since it should always be present in the
response from an authoritative server and can just be passed through).

I bring this up because in the specific context to which the original
poster referred -- the reference to "glue" in the debug output of
"nsupdate" -- I think the word is meant in the more generic sense, i.e.
nsupdate is just trying to get the A records so it can send its Dynamic
Update to the right place.

Frankly, I wish people wouldn't use "glue" in this generic sense. It's ve=
ry
confusing. It's bad enough that "glue" is a rather embarrassing term to
begin with (are we trying to build nameservice infrastructures or model
airplanes here?), let's not make it *ambiguous* as well...


- Kevin

Mathias K=F6rber wrote:

> A glue record is an A record in a parent zone for
> an NS record whose RHS is in the zone delegated by
> this record:
>
> Example:
>
>         somezone. IN NS ns1.somezone.
>
> note that the name of the nameserver ends in the
> zone delegated (somezone). This creates a problem, in
> that to be able to fins the address of ns1.somezone, one
> would have to query the nameservers of somezone, one of
> which is ns1.sonezome, whose address we are trying to find.
> (similarly to tell someone asking for the number of directory assistanc=
e
> to call directoryt assistance for it).
>
> Thus, the parent zone will have to include the address record for
> this nameserver as a type of 'hint'. These A records are called
> glue. They are not required if the nameserver named in an NS record
> is not located in a different zone:
>
>         somezone. IN NS ns1.otherzone.
>
> HTH HAND
>
> > -----Original Message-----
> > From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org]On
> > Behalf Of Kenneth Porter
> > Sent: Thursday, December 28, 2000 09:27
> > To: comp-protocols-dns-bind at moderators.isc.org
> > Subject: "glue" record?
> >=3D20
> >=3D20
> >=3D20
> > On Wed, 27 Dec 2000 23:21:55 GMT, Barry Margolin wrote:
> >=3D20
> > >However, there's no glue record for ns1.geeqsquad.com in the=3D20
> > geeqsquad.com
> > >domain,
> >=3D20
> > I hadn't seen the term "glue" record before this week, when I first
> > tried nsupdate and saw it trying to find "adequate glue" for a query.
> > What is a glue record? (Feel free to point me to the right docs that
> > explain this.)
> >=3D20
> > Ken
> > mailto:shiva at well.com
> > http://www.sewingwitch.com/ken/
> >=3D20
> >=3D20
> >=3D20
> >=3D20