[winswitch] Unable to connect from Windows client to RHEL 7.4 xpra server using SSH (v2.3.2-r19729)

[Ben Jackson]

Hi,

I'm completely new to Xpra, so please forgive me if I'm not providing the right diagnostics ;)

Quick summary:

when trying to connect xpra from Windows 7 to RHEL 7.4 over SSH, the connection fails with the following message:

2018-07-13 12:21:02,765 Error: failed to receive anything, not an xpra server?
2018-07-13 12:21:02,765   could also be the wrong protocol, username, password or port

The client and server versions are the same, and the ssh connection appears to work in any other context I can try it.

Detail:

My setup is:
- Server:
  - RHEL 7.4
  - Xpra 2.3.2-v19729 using the yum repo (I tried the latest 2.3.3-..., but downgraded to ensure the client/serer were same version for testing)
  - Python 2.7.5
  - public key in authorized_keys
- Client:
  - Windows 7 Pro
  - Xpra 2.3.2-v19729 (latest MSI on website)
  - Python 2.7.9 (not sure if the windows package uses python from my path)
 - Pageant running with private ssh key

I have installed Xpra as above and started the server successfully with "xpra start --start=xterm :1002".

However, when I attempt to connect from windows to the server using "Xpra_Cmd attach ssh://ash@ukwok-pc1385-vpc7/1002" it fails to connect and  I get the following.

2018-07-13 12:20:59,173 Xpra gtk2 client version 2.3.2-r19729 64-bit
2018-07-13 12:20:59,179  running on Microsoft Windows 7
2018-07-13 12:20:59,363 Warning: failed to import opencv:
2018-07-13 12:20:59,363  DLL load failed: Invalid access to memory location.
2018-07-13 12:20:59,363  webcam forwarding is disabled
2018-07-13 12:21:00,192 GStreamer version 1.14.1 for Python 2.7.15 64-bit
2018-07-13 12:21:00,593 OpenGL_accelerate module loaded
2018-07-13 12:21:00,627 Using accelerated ArrayDatatype
2018-07-13 12:21:01,296 Warning: vendor 'Intel' is greylisted,
2018-07-13 12:21:01,296  you may want to turn off OpenGL if you encounter bugs
2018-07-13 12:21:01,357 OpenGL enabled with Intel(R) HD Graphics
2018-07-13 12:21:01,428  desktop size is 3000x1920 with 1 screen:
2018-07-13 12:21:01,428   Default (793x508 mm - DPI: 96x96)
2018-07-13 12:21:01,428     DISPLAY1 1920x1200 at 0x381 (677x423 mm - DPI: 72x72) workarea: 1920x1200
2018-07-13 12:21:01,428     DISPLAY2 1080x1920 at 1920x0 (381x677 mm - DPI: 72x72) workarea: 1080x1920
2018-07-13 12:21:01,442  keyboard settings: layout=gb
2018-07-13 12:21:02,765 Error: failed to receive anything, not an xpra server?
2018-07-13 12:21:02,765   could also be the wrong protocol, username, password or port
2018-07-13 12:21:02,765 Connection lost

(Full client and server log output with debug can be found in this gist: https://gist.github.com/puremourning/36d6beb1d0baefe3cb0b79ec7cbfe3dd).

The server log does not change during the process (tailing /var/user/<uid>/:1002.log).

I'm looking for some advice on how to debug this. It looks like an environment issue (xpra doesn't seem to be getting any data back from plink?), but I'm a bit stuck.

Some things I have tried/confirmed:

- Using unauthenticated TCP _does_ work, but is not allowable in corporate env due to infosec.
- Using PuTTY to connect to the host works (ditto using putty's plink to echo hello). No password is required (pageant is working) (command putty\plink.exe -ssh ash at ukwok-pc1385-vpc7 echo hello). Hello is echo'd.
- Using the bundled plink.exe (tortoise?) to connect to the account/host in question, no password is requested, but "hello" is *not* printed (command: plink -ssh ash at ukwok-pc1385-vpc7 echo hello)
- Before setting up pageant (i.e. ssh-agent), all the above were tested while entering the account password manually, with the same results.
- Using a proprietary windows x-server, I am able to connect to xpra from the server (i.e. to itself) with xpra attach. (i.e. start an xterm with display pointed at windows X server, attach to xpra, see xterm)

Many thanks for any advice you may be able to provide. Naturally if there is any further information I can provide, just shout!

Cheers,
Ben



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