Watching performance on a DHCP Server
dhcp1 at thehobsons.co.uk
Sun Apr 27 06:41:45 UTC 2008
Anders Rosendal wrote:
>The biggest problems with intensive DHCP-storms due to network
>outages longer then leasetime is that if the server, or cluster of
>servers is not quick enough to provide answers is that the request
>made by the clients times out before the client receives a answer
>from the server. This causes the server to only answer requests that
>are "old" and no clients receives there addresses. The solution to
>implement when stuck in this situation is to block requests in the
>routers for large part of the network, and then bit by bit opening
>up everything again. On the company which I work we have an inhouse
>built DHCP-server which is quite powerful, we have ~550000 leased
>IP's in the system. Althoug when we have had long outages we have
>been forced to used the solution described above. You should monitor
>the udp-in-queue on the server / servers, checking that the server
>manages to answer clients quickly enough.
Does this mean that a smaller udp queue would be better ? Ie, throw
away excess requests (the client will try again soon) rather than
allow them to get stale ?
Or in some situations, rate limiting DHCP packets in the routers ?
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