cname quick question

[Cricket Liu]

> Can we please keep this in the newsgroup?
>
> Sure, sorry.
>
> > So why is nslookup returning an SOA record?  Shouldn't it say something
> > else?
>
> What you showed was nslookup returning the SOA
> record for the target of the alias, which is exactly what
> it should do.  It can't return the SOA record for the
> alias because there isn't one.
>
> So, if CNAME records have no SOA - then how often will they
"refresh/retry/live in the cache", etc?

A CNAME record--like any resource record--has a TTL associated with it
that tells name servers how long it may be cached.  In master file format,
the
TTL is usually the field between the domain name that owns the record and
the record's class.  Here's a CNAME record from move.edu:

# dig any bigt.movie.edu.

; <<>> DiG 9.1.0 <<>> any bigt.movie.edu.
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26291
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 3, ADDITIONAL: 4

;; QUESTION SECTION:
;bigt.movie.edu.                        IN      ANY

;; ANSWER SECTION:
bigt.movie.edu.         86400   IN      CNAME   terminator.movie.edu.

The "86400" is the TTL, in seconds.  This means that name servers should
cache this record for at most one day.

The refresh and retry values govern how long slave name servers for a zone,
not an individual resource record, wait in between checks of their master
name server.

cricket