Some Windows Clients Use Wrong Subnet

[hemojr]

We just recently migrated from a VPN based corporate WAN to an MPLS
based WAN.

In both cases DHCP services were/are provided by a central Windows 2003

DHCP server configured for multiple scopes. With VPN, we were using
Netopia routers as bootp relay agents. With the MPLS we are using
Netvanta routers as bootp relay agents.


In the MPLS scenario there are serveral DHCP clients that ending up
with class A subnet masks when DHCP should be configuring them
with class B subnet masks (our private addresses are 10.x.x.x -- class
A -- but we are subnetting using class B masks). The clients
exhibiting this behavior are older ones, Windows '98 and possibly
Windows '95 machines. This problem has not shown up on clients local to

the DHCP server.


Is there some sort of bug or idiosyncrasy in these older clients that
the Netopias may have compensated for, but the Netvantas do not?


Thanks

 

[Phillip Windell]

Most likely the client are not being "interpreted" as being on the correct
"wire" and so the DHCP is giving an address from the wrong scope.

This could also happen if the DHCP is configured with Superscopes,...there
should not be any Superscopes,..get rid of them if there are.

I think I am about "acronymed to death" today,...I have no idea what MPLS
is.

 

[Guest]

Check to make sure they aren't getting the address from the relay agent using
BootP. BootP doesn't supply a subnet mask. Make sure BootP is disabled (if
possible) and the routers are only relaying DHCP. Windows DHCP will respond
to both BootP and DHCP requests.

 

[Guest]

continued:
There is usually seperate commands for each, should you want to provide a
subnet mask or DNS server. By default it will only give an IP. Use DHCP if
possible.