how is a named resolved?

Praveen Kumar Amritaluru praveen at india.hp.com
Thu Apr 6 15:10:11 UTC 2000


Hi Kevin,

        I was under the impression that nameserver delivered by IISC is
recursive server by default. Are the root servers not running BIND on
their machines, or they have made it iterative.    I checked it locally using
three machines, and nameservers seem to work recursively.

        Please correct me if I am wrong.

Regards,

Praveen


Kevin Darcy wrote:

> The flow would normally be Figure 2, which shows normal iterative resolution.
> What is probably confusing you is that sometimes people set up their
> nameservers to "forward" to other nameservers, which means they act as clients
> and expect the forwarder to resolve the query for them. If B (a .com
> server) and C (a server for bbb.com) were setup in a forwarding hierarchy
> pointing towards the root, then Figure 1 would be correct. But such forwarding
> hierarchies are not feasible on the Internet, since the root servers and the
> .com servers do not perform recursion. Forwarding hierarchies are therefore
> normally only found on intranets, and usually because the internal clients
> need to resolve Internet names, but only certain nodes on the network (e.g.
> firewalls or nameservers in the DMZ) have the necessary connectivity to
> resolve those names.
>
> - Kevin
>
> flybird wrote:
>
> > Hi,all
> > I have a question about how named is resolved.
> > For example, there is a DNS server "A" which manage a domain and is a cache
> > server for root domain. So while it get a query for aaa.bbb.com, it will
> > query root DNS "B". And suppose DNS for com is "C", DNS for bbb.com is "D".
> > And than will DNS "B" query the "C" for aaa.bbb.com or it just reply to "A"
> > that DNS for com is "C" and then "A" query "C" for aaa.bbb.com ?
> > There are tow figure below to help me express my question:
> >
> >  1    2    3
> > ---> ---> --->
> > A    B    C    D
> > <--- <--- <---
> >  6     5    4
> >     Figure 1
> >
> > OR
> >  1
> > --->
> > A    B
> > <---
> >  2
> >
> >  3
> > --->
> > A    C
> > <---
> >  4
> >
> >  5
> > --->
> > A    D
> > <---
> >  6
> > Figure 2
> >
> > In my impression, the flow of DNS query is Figure 1. But After i saw the
> > discuss "Private Public DNS question" in this group, it seems the flaw is
> > Figure 2. Now i don't know which one is true.
> > Thanx for any help,
> >
> > Pan Tao

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Praveen Kumar A
HP ISO(B)                               phone: 91-80-225 1554 x1306
Bangalore, INDIA                        mailto:praveen at india.hp.com
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