Network in multiple shared-network instances

Simon Hobson dhcp1 at
Wed Apr 15 19:11:25 UTC 2009

Alex Moen wrote:

>How is this possible to do, other than combining all of the 
>configurations into one big shared-network statement and making a 
>very difficult config to work with?

I don't see that it is possible.

>Why is it a problem for a subnet to reside in more than one shared-network?

Because it's a BROKEN network config which is NOT valid. It is 
physically impossible for a subnet to be present in multiple 
different shared networks without breaking IP routing rules.

The answer is that you need to get your access equipment fixed. If a 
client is in a different VLAN, then the relay agent MUST also be 
present on that VLAN. If the relay agent is using a GIAddr which is 
on a different subnet/network then it is broken and DHCP will not 
work properly.

Simon Hobson

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