DHCP Relay and Redundant DHCP Servers, sync dynamic leases??

RouterOS General
1

DHCP Relay can have more than one server, so if there are two, how do the DHCP Servers sync their lease data?

I can see if both servers hand out an entirely different range of IP addresses then this would work, but with public IPv4 it is wasteful.

Is there any way to have redundant DHCP servers on Relay with the SAME IP Pools?

If so, how do the DHCP Servers know what each other has handed out dynamically?

Is anyone doing this, and if so, how?

Or does Mikrotik DHCP Relay and both DHCP Servers somehow coordinate things so no duplicate IP’s are handed out?

2

would be like to see a dhcp failover setup on MT too :pushpin:

3

Most don’t. An exception was Netware 5 where DHCP database was in NDS and shared by the servers. Some fancy Enterprise systems might do similar.

Regarding conflicts DHCP servers should test that an address is free using ICMP or ARP (local only) and exclude the address as a conflict if it’s already in use.

4

Microsoft DHCP Server can do what you ask, i.e. replication and lease sharing. You can learn more here

With MT there’s a thing called authoritative dhcp and delay dhcp, so you can have “active-backup” dhcp with mikrotiks kinda easily, but syncing configs and static leases is up to you, also no guarantee backup server leases same IP to the client as primary did. DHCP standard says client may ask for the same IP as he used previously, but it’s up to server to admit it or just ignore and lease whatever is free.