How to tell if an ssh session is using x forwarding (if it was run with -X or -Y)

Question

For a given ssh session, is there a way to tell if it has x-forwarding enabled? I.e. you don't know if the session was established with ssh username@address or with ssh -X username@address.

score 4 · Accepted Answer · answered Feb 18 '14 at 17:23

4

One simple indication is to look to see if a valid looking DISPLAY variable is set. If no display is set, you can be almost certain forwarding is not working properly.

$ export | grep DISPLAY
declare -x DISPLAY="localhost:10.0"

answered Feb 18 '14 at 17:23

Zoredache

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How to tell if an ssh session is using x forwarding (if it was run with -X or -Y)

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