Fix the Pulse Secure VPN HTTPS issue inside WSL 2

fix_wsl_2_vpn.md

This is my solution for:

Pulse Secure VPN

1. PowerShell: netsh interface ipv4 show subinterface
2. WSL2: ip link list
3. WSL2: sudo ip link set dev eth0 mtu 1400

Notes

1. I ran this after successfully connected to the VPN. I noticed an extra Local Area Connection* with an MTU value ~100 less than the other "Local Area Connection" entries. That's the value I wanted.
2. Inside WSL2, check what your eth0 mtu value is set to. It was not the MTU value discovered in Step 1.
3. Inside WSL2, set the MTU value of the interface eth0 to the value discovered in Step 1.
4. HTTPS IS NOW WORKING 🎉

notes

PS C:\Users\jbrinkma> netsh interface ipv4 show subinterface

   MTU  MediaSenseState   Bytes In  Bytes Out  Interface
------  ---------------  ---------  ---------  -------------
4294967295                1          0     106497  Loopback Pseudo-Interface 1
  1500                1  150893865    9953399  Wi-Fi
  1500                5          0          0  Ethernet
  1500                5          0          0  Local Area Connection* 1
  1500                5          0          0  Bluetooth Network Connection
  1500                5          0          0  Local Area Connection* 2
  1500                1          0     104338  vEthernet (Default Switch)
  1400                1    5644338    1703838  Local Area Connection* 12
  1500                1     154579     103532  vEthernet (Ethernet)
  1500                1     137829      91983  vEthernet (Wi-Fi)
  1500                1          0      59317  vEthernet (WSL)
  1500                1      36201      33380  vEthernet (Local Area Conn)
  


NOTE: "local area connetion" mtu=1400

$ ip link list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:7c:38:b3:d6:6b brd ff:ff:ff:ff:ff:ff
3: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 6e:a1:9f:b4:1a:85 brd ff:ff:ff:ff:ff:ff
4: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 00:15:5d:01:3d:c0 brd ff:ff:ff:ff:ff:ff
5: sit0@NONE: <NOARP> mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/sit 0.0.0.0 brd 0.0.0.0
    

NOTE: eth0 mtu=1500

sudo ip link set dev eth0 mtu 1400