DHCP server fail-over and accounting

John Adams jna at retina.net
Wed Feb 2 09:38:48 UTC 2011


2011/2/1 Joe <sj_hznm at hotmail.com>:
>
> hi,
>
>    we plan to implement DHCP server farm in our network.   Currently , there are there  problems burning my head. could anybody


You're making this way, way too complicated.

Run two DHCP servers. Allocate two different netblocks to each server.
For Example, if your network is a /24, allocate a couple of /26's.
Both will answer on a request.
The client will ack to whatever address it decides to accept. Full redundancy.

>       To our experience, this needs to set up  DHCP  server on two sites and syncronize their content in real time.
>      Beside this ,  we hope  there should be as less modification as possible  on edge router when one DHCP  server is down.
>      should anycast architecture helpful ?   or should we just set up two dhcp servers on two sites and  sync. with ISC DHCPD?

Don't even bother with the syncing, and anycast is the wrong protocol here.

>  2. How to set up accouting and authentication with DHCP?

That's the wrong place to do it.  802.1X is better here, or PPPOE/ACLs
that need RADIUS auth to get past.

> 3.  Someone said PPPOE is not good for customer looking for long time online ,  DHCP is an good option.  But, to my understanding

That's funny, because many major ISPs (like telcos) have done this for years.

-j




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