Remote extension at home office with dynamic IP

I have my FreePBX 13 box at my office. We have a static IP at the office.

I want to have a remote extension at my home office. Problem is, my home ISP does not offer static IPs, only dynamic. That means my home IP will change (once a day, once a month, no one knows and I noticed it is random). And that means I can’t program in an IP at the firewall at work or the FreePBX box itself.

So what would be the best practice for this? I checked and that doesn’t say a lot.

I don’t have a VPN at home because, since everything I do is cloud-based, I don’t need a VPN. Would like to see what I can do without doing a VPN just for the phone, but I can do it if that is the only option.

One solution is to note what your current external ip is


then see what the underlying network is

whois $(curl -s

look for CIDR: and white list that network, if there is no CIDR there would likely be a NetRange: , use that

whois $(curl -s|egrep -i “cidr|netrange”

might be simpler

Can’t you enable the responsive firewall? It allows extensions to attempt registering from any IP then if they fail so many times they get blocked. Just make sure you have a good Password. It works great for our dynamic IP customers, we used to have to add their IP non-stop.

Responsive works, alternatively if you have DDNS service running at home, you can white list the FQDN in firewall. Or do both, in a belt-and-suspenders approach.


Another option would be to set up a home network->PBX (or home network <-> Work network) VPN.

If you decide you want to do that, let me know. I cannot get my head around how to do it, but I’d love to figure it out.

DDNS would be faster and easier to set up, but I really would love to figure out how this VPN thing works…

DDNS client at the remote site. Enter your given URL into the whitelist on your freepbx server and mark it as trusted.

5 min very effective solution. Set your ddns client to check for changes often … I set mine to 600 seconds normally.

Talking here about DDNS. Which company do you guys suggest? What is working great and not expensive?

I’m using duckdns and, both are free and working great, no need to confirm after 30 days like noip, in case your ip doesn’t change that often.

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