I am currently finishing up the testing stage of a 3CX deployment using Yealink T38 sets. I have the server running, a test SIP trunk set up with my VoIP provider and a couple extensions working. I'm able to do all of the basic functions. I'm running 3CX in Hyper-V and have the VM replicating and backing up to a second server. What I would like to do now is add a second SIP account to the autoprovision so the phones can be used on or off of my local network. I can set the phone to just use the public FQDN but would prefer to be able to add a second account as my failover facility has a different public IP. In the event my primary site is down, i'd have to change the DNS records then wait for all of that to propagate before the phones would register with the backup 3CX server. What is the best way to accomplish my high availability setup? I can provide more information if necessary.