Fixed Lease DHCP Doesn't Work After Connecting Different Network

[John Shwon]

At my office the DHCP server leases me a specific IP address based on my MAC
address. I require this IP to use certain network services that are
restricted based on IP.

Everytime I use my laptop on another network and get leased an IP and then
return to the office I don't get my "fixed lease" IP based on MAC address.
The only way to get my assigned IP again is to assign myself a fixed IP and
then change back to DCHP. Somehow, these actions reset something so that I
get leased the correct IP again..

Why is this happening and who can I fix it without assigning myself a fixed
IP, applying and changing back to DHCP.

BTW - I'm not using wireless.

Thank!

 

[smlunatick]

At my office the DHCP server leases me a specific IP address based on my MAC
address. I require this IP to use certain network services that are
restricted based on IP.

Everytime I use my laptop on another network and get leased an IP and then
return to the office I don't get my "fixed lease" IP based on MAC address.
The only way to get my assigned IP again is to assign myself a fixed IP and
then change back to DCHP. Somehow, these actions reset something so that I
get leased the correct IP again..

Why is this happening and who can I fix it without assigning myself a fixed
IP, applying and changing back to DHCP.

BTW - I'm not using wireless.

Thank!

The DHCP service(s) do not release the IP address once you disvconnect
from the network. In order for the DHCP "client" (your's) to re-
request an DHCP based IP address on next boot-up, you need to issue
the following at the Command Prompt:

 

[Lanwench [MVP - Exchange]]

At my office the DHCP server leases me a specific IP address based on
my MAC address. I require this IP to use certain network services
that are restricted based on IP.

Everytime I use my laptop on another network and get leased an IP and
then return to the office I don't get my "fixed lease" IP based on
MAC address. The only way to get my assigned IP again is to assign
myself a fixed IP and then change back to DCHP. Somehow, these
actions reset something so that I get leased the correct IP again..

Why is this happening and who can I fix it without assigning myself a
fixed IP, applying and changing back to DHCP.

BTW - I'm not using wireless.

Thank!

This is normal but you're making life harder than you need to to fix it.
Either use ipconfig /release ....ipconfig /renew, or repair your connection
by right-clicking on it.

 

[John Shwon]

I tried ipconfig /release, and ipconfig /renew but I would not get the
correct IP assigned. I even tried "nuke-ing" my network stack using the
command on Scott Hanselmann's blog, but I still had the incorrect IP. The
only way that I found that works is speciying a fixed IP and then changing
back to DHCP.

Any idees?

 

[Lanwench [MVP - Exchange]]

I tried ipconfig /release, and ipconfig /renew but I would not get the
correct IP assigned.

What do you see in ipconfig /all after you try this? What's the DHCP server
address? Shouldn't be the one on the network you aren't connected to!

I even tried "nuke-ing" my network stack using
the command on Scott Hanselmann's blog, but I still had the incorrect
IP. The only way that I found that works is speciying a fixed IP and
then changing back to DHCP.

Any idees?

What about repairing the connection, as I suggested?

One way around this would be to do an ipconfig /release *before* shutting
down on 'the other network" ....then when you boot up in your office you
should getthe correct IP.