If a PC with a DHCP server is connected via VPN, with it serve IP addresses over the tunnel?

[salquint11]

Situation:  We have some Ubuntu test laptops running DHCP servers.  We need to get updates and other changes from the corporate network occasionally.  Today we disable the DHCP server, set up to get an IP address via DHCP (from somewhere else), and do our updates.

Problem: We don't want anyone to accidentally connect the laptop to the corporate network while its DHCP server is running.

Question: So, if we go via wifi using Cisco VPN client software, will the DHCP server serve IP addresses over the tunnel?

Thanks for reading.

[jj27 · Accepted solution]

No. DHCP uses layer 2 broadcasts to serve IP addresses.  Since your clients are connected via the VPN, there will be no layer 2 adjacency.  The only way it would accidentally do it is if you configured an IP dhcp helper address to be one of your VPN clients on the network, which I would imagine you wouldn't do.