Nameserver records outside current domain

[Len Conrad]

>Was looking at my DNS records

uh oh  :)))

>In a multiple-domain hosting environment, where the primary domain is 
>foo.com.  The entry for bar.com has:
>@       IN      NS      ns1.foo.com
>@       IN      NS      ns2.foo.com
>
>Now since all the other records in this bar.com domain all resolve to IP 
>addresses, how does the NS records resolve to an IP?  Does it have to do 
>another lookup for foo.com to find these?

When a DNS queries the .com parent for bar.com, the .com parent returns a 
"referral" that looks like this:

;delegation data
bar.com. Ns ns1.foo.com.
bar.com. NS ns2.foo.com.

;glue records
ns1.foo.com a ip.ad.re.ss
ns2.foo.com a ip.ad.re.s2

The querier doesn´t have to resolve the ns ip´s, they are in the 
"additional section" of the referral.

Len



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