about the reference
lyle at lcrcomputer.net
Fri Jul 1 13:07:22 UTC 2011
On 07/01/11 03:47, Jeff Peng wrote:
> Please see this reference:
> $ dig mydots.net @j.gtld-servers.net
> ;<<>> DiG 9.4.2-P2.1<<>> mydots.net @j.gtld-servers.net
> ;; global options: printcmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41902
> ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
> ;; WARNING: recursion requested but not available
> ;; QUESTION SECTION:
> ;mydots.net. IN A
> ;; AUTHORITY SECTION:
> mydots.net. 172800 IN NS ns1.dnsbed.com.
> mydots.net. 172800 IN NS ns2.dnsbed.com.
> ;; ADDITIONAL SECTION:
> ns1.dnsbed.com. 172800 IN A 18.104.22.168
> ns2.dnsbed.com. 172800 IN A 22.214.171.124
> ;; Query time: 196 msec
> ;; SERVER: 126.96.36.199#53(188.8.131.52)
> ;; WHEN: Fri Jul 1 16:23:05 2011
> ;; MSG SIZE rcvd: 106
> j.gtld-servers.net gives the reference info about the domain mydots.net.
> It says the dns servers for mydots.net is ns[1-2].dnsbed.com, following with two NS's IP addresses.
> My question is, when other BIND Cache get this reference, will it use the IP addresses directly?
> Or will it use the IP addresses get from the authoritative server?
> I ask this because, when the IP addresses get from reference, are different from the ones get from the authoritative server, what will be happened?
> Thanks for your kind helps.
Think about this scenerio:
example.com uses ns1.example.com and ns2.example.com for it's name
servers(legal and proper).
If the resolver did not use the glue records presented from the root
servers, how would the resolver find www.example.com?
When you register name servers, these are called glue records. The info
in the additional section, comes from those glue records.
In your scenerio, the results will be unpredicatable and random.
Sometimes it will work and sometimes it won't work. It's important that
the glue records be correct.
LCR Computer Services, Inc.
More information about the bind-users