Managing DNS between branch offices?

[incirrata]

I have OPNsense firewalls deployed to two different offices that communicate with each other via IPsec tunnels. The trouble is that I need to somehow keep the DNS records of 300+ hosts consistent between the two. It would be a hassle to change both firewalls every time there is a change in one location. Is there some way to sync DNS between two different firewalls in two different physical locations?

[Ren]

Are you using opnsense at both locations for dhcp and to register those dhcp leases to dns resolver?

Do both locations have separate domain names?

If so you can add a domain override on each router to allow the remote subnet to query their dns servers .

Example:
SITE A domain name is fries.local (192.168.2.1)
SITE B domain name is burger.local (192.168.3.1)

Site A pc needs to find a PC on Site B network by hostname. I can create dns record on site A or tell the router that any incoming query for domain burger.local send it to site B's dns server to resolve