Fix PaloAlto GlobalProtect VPN / Cisco AnyConnect VPN issue over iPhone tethered hotspot in T-Mobile network

Description

  • When connecting to hotspot tethered by iPhone with GlobalProtect VPN or Cisco Any Connect VPN, the connection may fail in changing IP forwarding table, caused by interesting T-mobile assigned NAT IP for iPhone.
  • It may not be caused by IPV6 or any cutting-edge 5G T-mobile is using, indeed, it may be caused by the IP range your iPhone supplies which conflicts your cooperate VPN network.
  • MTU change may not work either

Steps to fix it

  • Just assign a static IP to your macOS Wifi. Here is the value I tested
IP Address: 172.20.10.5
Subnet mask: 255.255.255.0
Router: 172.20.10.1

(Subnet mask is required too)