one to know one thing

frajo

Two router R1 & R2, to both router switch is connected S1 & S2 .
To S1 pri DNS and a host is connected Host 1
To S2 sec DNS and a host is connected Host 2

When we try to ping thr ip addrs or hostname everything works fine so routing table is configured properly.

One to know one thing where me and my instruter are not on same side.

Cisco router block broadcast by default.
Prim dns have entry of Host 1 only and vice vers for Sec Dns
Prim dns will have entry of sec dns i.e ipaddr so it can forward the request to sec DNS.

But my inst say that on host when enter static pri and sec DNS that can do it.

If it doesnot make any sense plz let me know i am new and any comment will help :

dtlokee

I am not exactally sure what the question is here but I think you're asking about the configuration of a primary and a secondary DNS server on a host. If the operating system is Windows based it will always use the primary DNS server only. The only exception to tis is if the primary DNS server does not respond withing the timeout period, then it will query the secondary DNS server. If the primary DNS server responds with an unknow hostname or domain name that is the answer, the host makes no attempt to query any other DNS server.

You are correct in that a Cisco router does not forward broadcasts (that is a L2 broadcast MAC address of FFFF.FFFF.FFFF or the L3 ip address 255.255.255.255 which resolves to FFFF.FFFF.FFFF) howerver the cas may be different for a directed broadcast (that is the highest IP in the subnet range). If the router has been configured with an IP helper address it will pick up any DNS broadcast traffic and forward it to the helper address.

HTH

Netstudent

wow...dlotkee I give you props for being able to understand that.

Frajo,

You have to be a little more explanatory with your problem and more concise with the question. I can barely understand what you are trying to say. PLease write in complete sentences and complete words.

It is hard enough to understand someone else's technical difficulties, but it makes it even more hard for someone to help you if they don't understand your problem or your question.

From what I gathered, dlotkee provided a pretty good explanation.

Anyways good luck!