Wrong DNS Address Received In DHCP Scope

By kweli ·
Greetings All:

I am managing a single domanin server wherein the IP Address of the DHCP and DNS Server is With regularity, various client machines will pull a scope with as the DNS Server IP address. When this happens all sorts of things stop resolving and causes errors accessing everything from file shares to e-mail that are located on All clients connect via Cisco Catalyst 2900XL switches.

Does anyone have an idea why the client machines get the faulty DNS IP address in there scope and what the source may be?

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All Answers

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errrr probably the catalyst's fault but....

by CG IT In reply to Wrong DNS Address Receive ...

check the DHCP option for DNS server see if it's got the right DNS address.

I'd check the catalyst though.

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I have similar issue

by philhartman In reply to Wrong DNS Address Receive ...

I also have a single Server 2003 network
where the server is the DC and DHCP server.
When workstations first turn on they get the
correct DNS from scope options (it is the
same as server address). Unfortunately,
they forget this DNS and somehow show the
forwarding DNS address after about a day.
The DHCP logs show the workstations requesting DNS updates, but these are failing. Any hints how to troubleshoot this?

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Having the exact same problem as Phil Hartman

by lorenzo In reply to I have similar issue

Same setup as Phil, exact same issue to the bone (incl. correct DNS suddenly changing to DNS forwarders). This problem did not occur prior to february this year in my network, and honestly I have no idea what I (or Windows Update) have changed that could cause this.
Some questions for you Phil:
- Do you have a router (or other hardware) on your LAN that has DHCP capabilities? If yes - have you disabled the DHCP on this hardware?
- How long is the lease time for your DHCP addresses? Do you know if the shift from correct DNS to DNS forwarders occurs when the clients try to renew the lease, because this seems to be the case in my network.

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rogue dhcp server

by sgt_shultz In reply to Wrong DNS Address Receive ...

this is a classic symptom of a rogue dhcp server. do you have somebody bringing in their wireless or other kind of router and sticking on the network? win2003 will only protect you from 'non authorized' dhcp servers if the are windows boxes.

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