Local DNS Forwarder.....

[deano050778]

#i have recently took charge of a 2003 server where all workstations point at the DNS server (which is the domain controller). It is then set to forward all dns requests to our ISP's DNS.

Can anyone tell me if this is what you would call a "local dns server" - does it actually resolve addresses to ip's if it has had to resolve it before? or does it just pass all DNS requests to the ISP?

Any links to websites - info on this would be greatly appreciated....

Thanks beforehand!

 

[Jpoandl]

This sounds like a typical small business setup. DNS is required for Active Directory (domain) to work. Therefore, when Windows 2003 was installed and the domain was created, DNS was installed locally.

You DNS server is probably registering computer on your network with DNS. So, your internal DNS server is performing all DNS services for your local clients.

With regards to Internet resolution, your DNS server is setup to forward requests to the ISP DNS servers. This means when a user is lookiing up

http://www.yahoo.com,

the query first goes to your local DNS server....and your DNS server forwards the request to the ISP DNS servers.



Joseph L. Poandl
MCSE 2003

If your company is in need of experts to examine technical problems/solutions, please contact

http://www.NJCOMPUTERNETWORKS.com

(Sales@njcomputernetworks.com)

 

[deano050778]

so am I correct in thinking if the DNS has been resolved for one workstation and another then requests the same page - our local dns won't need to forward the dns request the the ISP again?

 

[aftertaf]

the local DNS server 'remembers' the hostnames it has resloved in the past.... they are stored in the cache...

if you change to advanced view on your dns server management console, you can inspect this cache..
so, yes, you are right

Aftertaf (david)
MCSA 2003

 

[deano050778]

Oh yeah - I can inspect it now. It only seems to have recent DNS requests though - are they only caches for say 12 hours or something?

Is there a standard struchture for DNS? i can see within mine we have au,ca,com,edu,fr,mil,net,org,uk etc...

 

[aftertaf]

DNS:
hierarchical structure for name resolution.

the root domain is . (but we never see it...)
there are 13 (i think) root servers on the net... that point to the servers that are authoritative for the first level domains:
the first level domains are .com, .org, .net, etc etc

they know which dns servers manage 2nd level domains, such as microsoft.com, tek-tips.com
and so on.....

(simplified, so not exactly 100% accurate, but:
when you query your dns server for tek-tips.com,
it asks a root server (.) who is in charge of .com, root replies with an ip address.
your dns server records the authoritative server for .com in its cache, then asks it who is the boss for tek-tips.com...

.com replies with an ip address for tek-tips.com...
, your dns stocks it in its cache and returns you the ip address for tek-tips.com.)
it first asks a root server

you can check and change the cache duration in the dns console, by right clicking on the dns server and hunting around on the different sections...
damn this NT4 domain, i'm forgetting all my w2k server basics!!!!!



Aftertaf (david)
MCSA 2003