CODEWITHSUNDEEP
ciscowindows-subsystem-for-linuxx11-forwarding
strydervtx
strydervtx

Reputation: 61

How can I get networking AND X11 forwarding in WSL 2 with Cisco Anyconnect?

So I can get X11 forwarding working in WSL2 following e.g., How to set up working X11 forwarding on WSL2. Then I had issues getting networking to function after connecting to a Cisco AnyConnect server, but I solved that using, e.g., WSL 2 Cisco AnyConnect Networking Workaround. This included manually setting up /etc/resolv.conf to include the DNS nameservers I need, although the DISPLAY variable for X11 should then be set via this answer to the X11 question.

But as soon as I connect to AnyConnect, I can no longer forward X11 apps, which even includes vim unless I add the -X argument (seemed odd, but what do I know). The apps don't show an error in display setting, they just don't show up. The same commands work fine as soon as I disconnect from the VPN. This happens regardless of the networking settings that need to happen, so I think it's only related to the AnyConnect itself, but perhaps there are additional Powershell commands I need to run so the display works? Any ideas?

Upvotes: 4

Views: 2040

Answers (1)

dosyfier
dosyfier

Reputation: 328

I had the same concern in my WSL2 environment. Once I opened a VPN connection via Cisco AnyConnect, the default network interface I had set within DISPLAY environment variable for X11 forwarding (which I retrieved from /etc/resolv.conf - same method as the one you pointed out) wasn't accessible anymore.

I looked then for any Windows network interface ping-able from WSL2 side and with a 6000 port reachable (since this port seems to be the one used by default to establish X11 connections with X servers like VcXsrv). And by luck, I found the virtual network interface opened for the Windows host on the VPN, which matches these criteria:

Name                       : Ethernet 2
InterfaceDescription       : Cisco AnyConnect Secure Mobility Client Virtual Miniport Adapter for Windows x64
InterfaceIndex             : 4
MacAddress                 : [...]
MediaType                  : 802.3
PhysicalMediaType          : Unspecified
InterfaceOperationalStatus : Up
AdminStatus                : Up
LinkSpeed(Mbps)            : 862.4
MediaConnectionState       : Connected
ConnectorPresent           : False
DriverInformation          : [...]

To be able to use it from WSL2 side, I used the following Powershell command to retrieve the interface's IP address:

Get-NetAdapter |
  Where-Object InterfaceDescription -like "*AnyConnect*Virtual*Adapter*" | 
  Get-NetIPAddress -AddressFamily IPv4 |
  Select-Object -ExpandProperty IPAddress

which can be wrapped into a Powershell call from WSL2, like following:

/mnt/c/Windows/System32/WindowsPowerShell/v1.0/powershell.exe -Command '<the_command_above>'

Once I got this IP address, I only had left to re-export my DISPLAY environment variable with it:

export DISPLAY="<vpn_ip_address>:0"

And that was it, I could enjoy X11 forwarding back again!

Upvotes: 1

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