Problem with Skype for Business?

Question

Skype

Please help, I've already broken my head. There is SFB 2015 in Std edition. It comes with EDGE in DMZ and IIS ARR (Reverce Proxy) in DMZ. I've already broken my head on this question, when configuring the firewall, I indicate that 3478 via UDP should be open. It seems to be open on network equipment, but I cannot verify this. But I can’t, because when I output the netstat -a command, I don’t see the Front End or EDGE listening to it. Maybe I did something wrong or where to dig. Everywhere it is written that it should listen and a connection client goes through it, but I don’t see it in the listing of ports. Please tell me how to make sure that the service going through it is working.