Two offers in response to one discovery

Simon Hobson dhcp1 at thehobsons.co.uk
Wed Dec 14 17:10:25 UTC 2011


John Miller wrote:

>A little more as to how Campus Manager works that might shed some light.
>Basically there are two pools; compliant and noncompliant. The MAC address
>of a client moves from one pool to the other depending on their state of,
>well, compliance with network policy. The move is done by either having or
>not having the client MAC address in the table of valid (compliant) MAC
>addresses. The situation with the client in question is that it was
>compliant, then became noncompliant, so yes, at one time it did have one of
>the IP addresses that is being offered. When the DISCOVER is sent, the
>packet does contain a request for its old IP address (option 50), but my
>understanding is that the server should ignore this since the client MAC is
>not in the compliant table (maybe a bad assumption). The server responds
>with the 2 offers; one for the requested IP and the other (correctly) with a
>non-compliant IP. The client only responds to the offer for wrong IP, which
>the server properly NAKS. This goes on for some time until the server
>finally sends an ACK for the compliant IP (like it gives up trying to do the
>right thing) and then my non-compliant client is sitting on the compliant
>network.

Probably time to be posting server logs and config files - obviously 
only relevant lines from the logs, and you'll need to thin out the 
config file.

-- 
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.



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