Bill,
Thanks very much for your response, I should have thought of
DHCPINFORM. In hopes of getting a clearer picture of what was
happening, I used Ethereal to do a packet capture of the related
traffic. First I released the address on the client, started the
packet capture, did an ipconfig /renew, and then waited until the DNS
scope options changed.
Here is what I found:
8:13:55AM
Client sent DHCPDISCOVER
Client sent DHCPREQUEST
Client sent Gratuitous ARP
8:41:48AM
Client sent DHCPINFORM
Server C sends ACK (Server with which the IP is registered)
Client sent ARP reply to Server B (The server which overwrites DNS
scope options)
Server B sends ACK
8:41:51AM
Client sent DHCPINFORM
Server C sends ACK
Server B sends ACK
A couple things that I would like to understand, please chime in if
anyone has any details.
1. Why does a client send a DHCPINFORM request nearly a half hour
after renewing the address?
2. Why after receiving DHCPINFORM ACK notices from two servers, would
the client send out another DHCPINFORM reuqest a few seconds later?
3. When the client receives the secondary DHCPINFORM ACK from Server B
which overwrites the DNS scope options, why does the order of the WINS
options not change on the client as well?
Thanks!
Troy.
Bill Grant wrote:
> When a client boots up, it broadcasts on the network to get its config
> from a DHCP server. The DHCP server replies with an offer.
>
> In addition, a client can send a DHCPINFORM message (after it gets its
> initial config) to receive additional information from a DHCP server. This
> info may come from a different source. As an example, a remote client might
> get its original config from a remote access server, then obtain additional
> LAN-based settings from the DHCP server on the LAN using DHCPINFORM.
>
> (E-Mail Removed) wrote:
> > I am having trouble understanding something that is occuring on one of
> > my client computers. I am in the process of bringing a new Windows
> > 2003 R2 DC online to replace an old Windows 2000 DC. Both servers are
> > running DHCP (with non-overlapping scopes), DNS, WINS. There is
> > another Windows 2000 server on the same network offering the same
> > services. My previous setup is as follows:
> >
> > All DHCP servers have non-overlapping scopes and each scope provides
> > scope options to point DHCP clients to DNS and WINS servers. When a
> > DHCP server offers a client an address, the options that it sends
> > always list the DHCP server as the primary server for DNS and WINS.
> > So for example, Server A gives out an address and the DNS options for
> > it would be Server A as the primary, and Server B as the secondary.
> > This has always worked without any problems. With the addition of
> > the new server I am seeing some very strange behaviour. In
> > particular, one client is getting a DHCP address from Server C (the
> > new server), but it's getting it's DNS scope options from Server B.
> > The WINS scope options on the other hand are coming from Server C as
> > they should be.
> >
> > If I release and renew the IP address on the affected client, it gets
> > all of the proper settings. It gets all scope options from Server C.
> > But, a few minutes later (5-15) when I check the client using IPCONFIG
> > /ALL, the DNS options have changed to those offered by Server B.
> >
> > Does anyone have any insight into why this is happening, or any
> > suggestions for how I would troubleshoot? There are no errors in the
> > event logs on the clients or servers, and dns resolution on all
> > servers seems to be working fine when checked with NSLOOKUP.
> >
> > Thanks,
> > Troy.
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