Enterprise Networking Design, Support, and Discussion. Enterprise Networking -- Routers, switches, wireless, and firewalls. Cisco, Juniper, Arista, Fortinet, and more are welcome.
Remote DHCP
I have a situation with some satellite offices that need network connectivity to the main office and the internet at large. I am thinking that using a VPN tunnel is the correct solution, but I am struggling to figure out DHCP.
I have two major options, setup a DHCP server on site, or a DHCP relay and get my information from the main office.
What is considered best practice? The DHCP relay seems to be less reliable because any number of links in the chain could break causing the DHCP to become unavailable, but I would miss out on many features like auto DNS population in AD by generating DHCP locally. How would y'all solve it?
For me this's always a question of "Can the remote office function without the VPN?"
If they're getting DNS over the VPN, or critical LOB applications are serviced across the VPN that they can't work without, then there's no point in having DHCP onsite because they're dead in the water without the VPN anyway - and given that, may as well take advantage of central management by relaying
Are your Internet links reliable? Do you have more than one at each site.
You should aim to use DHCP relay as it will be less admin overhead in the long run.
Set up 2 servers centrally and set them up in load balance mode.
I'd be more concerned about timing problems from potential WAN delays. I'd definitely suggest local dhcp servers.
It's a local survivability question. Does a location have local servers that would still allow them to get work done if their Internet connection went down? Do you have VoIP phones with a local gateway to maintain emergency call services? If so then an on-prem DHCP server makes sense. If not there is really no problem with your DHCP server being in the cloud or at HQ. If you're doing on-prem DHCP you should also be doing on-prem DNS. Having an IP is only half the battle.
DHCP is pretty resilient by design. It won't be sensitive to WAN latency or even some dropped packets. Whatever you do implement, though, you should have redundant DHCP servers through multiple relay destinations.
Centralized DHCP and longggg leases if it’s a site with fairly “static” device patterns.
