UDP or HTTP in server address?

I’ve noticed that some installations appear to have UDP for the server address and others have HTTP. Should I be concerned about this and why are they differing? AFAIK they have all been deployed via the same method. UDP and TCP (which is I assume what HTTP uses) are both allowed through the firewall.

PS. Really must get around to putting an SSL certificate on there!

No need to be concerned. UDP registrations are more scalable and use a bit less bandwidth. HTTP registrations are more commonly possible though, since UDP is blocked on some networks. We send the same data over both protocols, so the server will not distinguish between the two.

We suggest using UDP in situations where there are going to be many registering services in order to reduce the load on the server. For most server installs though it shouldn’t make any material difference.

Ahh okay, so the client tries both and if UDP gets through, it uses that?

We have a few vms that use http.