Here's my set up below, this works perfectly fine with Asterisk but from what I understand 3CX needs STUN and I can't get it to work with any of my Cisco phones. We use DSL right now, 10Mbps down and 7Mbps up and have 2 users in the office then will have 1 user working from home. I don't have a static IP as it's a rip off with my ISP so I use a dynamic dns service so I have a .com domain that always points to my current IP. I have Cisco phones and Polycom right now. Cisco doesn't work at all as it doesn't support STUN so I don't think I'll be able to use those unless it's somehow possible? I have one Polycom and the 3CX site says sometimes you can get them to work with NAT Traversal but I tried for awhile and had no luck. I have issues getting it to work even on the local network anyway though. So was looking at Snom or Grandstream etc. Was just wondering if one particular model is better than another for remote extensions, or would it make more sense to provide my teleworking employee with a VPN router that connects back to my office over VPN and then have them just use the Cisco phones as well? Not all that familiar with how STUN works, I see it says to enter stun.3cx.com as the STUN server on the phones, but how does that server know what my phone is? Is my PBX talking back to that server as well or something or do I have to do further configuration? Thanks so much!