Re: DHCP on SBS

In news:41CB3B6A-FF2C-44F9-88DE-47FFB0F8BF3C@xxxxxxxxxxxxx,
Alan <Alan@xxxxxxxxxxxxxxxxxxxxxxxxx> typed:
Is there any way you can stop the SBS DHCP server function shutting
down when it detects another dhcp server?

I don't think so - but read on.

I had a call from a client this morning telling me that no-one could
connect to the server. The cause! Bell South replaced a DSL
modem/router in one part of the network with a new one, because the
old one was misbehaving. In typical fashion they did not turn off the
DHCP server function of this router and people started pulling IP
addresses from it which naturally didnt have the SBS server IP
address in the DNS settings.

So even if the DHCP server were stil running on SBS at that point, you'd
have no way to ensure that it was the one that dished out addresses. Whoever
answered the clients first, would do it.

As the users all shut down their
computers each night they pulled a new IP address when starting up
this morning and copped the typical huge delay when connecting to the
server when DNS is wrong.

I was lucky to discover the cause and only realised what was going on
when I did an IP config on one of the systems and discovered a
strange gateway and dns address.

I then asked the question, has anyone installed some new network
hardware recently? and then got told that Bell-South had been in
yesterday.

So I got onto Bell-South (and that can be a real achievemnet
sometimes) obtained the router Password and turned of DHCP.

As the SBS server is on a faster link than the part of the complex
where the new router was installed I feel confident that had the DHCP
service on the server not shut down, they would have pulled the
correct addresses without IP adr conflict (the server uses 50-99 as
its range and the bell-souther router used 101 onwards)

But it would have been nice if SBS had not shut down its DHCP server
service.

You can't functionally work with two DHCP servers on the LAN - unless
they're configured properly with non-overlapping scopes.

The right solution to the problem above is: your clients should be notifying
*you* before any vendor comes in and replaces any kind of network equipment.
I'll bet they've learned that lesson now, right?

I'm not sure why you have this additional modem on your LAN anyway - what's
it for, and why is it connected directly to your LAN rather than to either a
separate hardware appliance (router) or the 2nd NIC of a properly-configured
computer/server ?


Alan

(in Australia, its already tomorrow)



.

Relevant Pages

  • RE: DHCP: not reached by clients
    ... Based on my research, we do not need to configure the DHCP or DNS on SBS, ... Run the Change Server IP address wizard to configure the SBS IP: ... One network adapter - manual router connection to broadband ... DHCP on router and other clients. ...
    (microsoft.public.windows.server.sbs)
  • Re: Problem
    ... the remote site and see if they have the connection manager installed. ... So...whichever is easier to set up on the router. ... location B need to connect individually via VPN to the SBS server at ... server - not sure of the clients ip scheme - but I think it is ...
    (microsoft.public.windows.server.sbs)
  • Re: VPN/RAS Access other network resources
    ... is my ADSL Modem Router Firewall. ... PPP adapter RAS Server Interface: ... > DHCP server for the LAN but VPN clients are issued IP addressess by the VPN ...
    (microsoft.public.windows.server.networking)
  • Re: A/D Dynamic DNS Update Problems
    ... When I say DHCP clients, I don not refer to Static ip clients. ... By default XP clients request IPs to an available DHCP server, and the DHCP server takes care of the rest. ... When the client dynamically updates its DNS information in this situation, the client's DNS time stamp is not updated until the Refresh interval takes effect. ...
    (microsoft.public.windows.server.active_directory)
  • RE: DHCP Scope split
    ... Reserved clients, recognised by MAC number, who must always be given a lease ... the DHCP server is not allowed to assign these. ... has a reservation on the address which is registered with the DHCP server. ...
    (microsoft.public.windows.server.networking)