dhcp problem

[carl_townshend]

hi all, i just had a big problem, whereas, i have a remote site with ip network 172.17.50.0, the router has 1 fa port with 2 addresses, 172.17.50.1 and 10.1.1.50 sec, this router is on the end of a lan extension. the problem is I set up a dhcp range in the 172.17.50.0 network and people at my remote office on the 10.0.0.0 network started getting offered dhcp on the 172.17.50.0 network from this site, why is this ?

[andrew.burns]

Hi,

Can you describe how you're providing DHCP services? from the router? or from a separate dhcp server? are you using helper addresses?

Andrew.

[carl_townshend]

i am providing them via the router, i guess the problem is because the interface has 2 ips and so is passing the offers back out that interface to the lan, could this be ?

[andrew.burns]

Hi,

I'll quote from the docs:

"If the interface has secondary IP addresses, the subnets associated with the secondary IP addresses are examined for possible allocation only after the subnet associated with the primary IP address (on the interface) is exhausted."

The available options in this scenario are:

1) Don't use DHCP for address allocation out of the secondary subnet

2) Use a manual binding, so that a particular device always gets a specific IP

HTH - plz rate if it does

Andrew.