DHCP

[RussellMcL]

I have an issue where a DHCP server is being replaced, and I need to find out a few bits and bobs about the workings of DHCP on a windows (2000?) server.

When the new server is connected, there are obviously devices on the lan which already have dynamic addresses. How does the new server find out what these are? If it is by pinging addresses, does it ping one at a time, or the whole lot? How long would it take to find 512 addresses?

 

[fregeama]

The new DHCP does not need to know the addresses that were given out by the old DHCP, unless they are reservations.

If the addresses are fixed in accordance to the MAC addresses of the clients, then you need to set them in the new device.

If they are not fixed, then the clients will simply ask for a new IP from the new server. Here is how it works

>Station needs to confirm its current IP address.
>It sends a message to the old DHCP server to confirm
>It does not reply
>The workstation then tries to ask and see if there is another DHCP server that can answer
>It sends a broadcast to find another server
>The new server identifies itself
>The client asks for an IP address
>The server gives an IP (a new one) and logs it into its DB.