I'm a new guy just learn to use OPNSense for few weeks, so as the title, can OPNsense run DNS Load Balance Service?
Yes, in theory you can run HAProxy on OPNsense in front of multiple DNS servers for load balancing.
If you are just after failover, then issue multiple DNS IP's to your clients (manually or by DHCP)
@bartjsmit do you have a working configuration example for that? While the commercial enterprise version (haproxy.com) claims to support UDP load balancing, the open source (haproxy.org) documentation reads to me like UDP is only supported for log forwarding. I might be wrong, the documentation is not really well organised and I might have misread it.
Sorry Patrick, theory only ;)
I wouldn't recommend load balancing DNS unless you handle very high volumes of queries, in which case you should really look at a separate DNS infrastructure with load balancing, highly available servers, etc. At that point you will likely have budget for F5.
Bart...
But then even in theory it is not possible with the community edition:
https://discourse.haproxy.org/t/i-am-not-able-to-enable-udp-traffic/9178
That was my last known state of features and it seems this is still the case.
nginx can load balance UDP.
https://docs.nginx.com/nginx/admin-guide/load-balancer/tcp-udp-load-balancer/
As for implementing in/with opnsense, pass.