Hello all, Please send a Cc: to me in addition to the list. I am not subscribed and this will make it easier for me to follow the thread and reply. Thanks. My scenary is as follows: I have a Linux server with OpenSSH 3.7.1p2 installed and this server acting as an LTSP. Some PCs (all Pentium+ classes) acting as X-Terminals connects to this server via PXE boot --> DHCP --> booting LTSP-kernel (2.4.24) --> executing XFree86 4.3.99 --> and finally executing "ssh -X user at linuxserver some_program" (same version OpenSSH as server) in order to execute the OpenOffice binary and nothing more. Thanks to the X-Forwarding feature, all the OpenOffice executes in a very capable Linux server for all PCs acting as a X-Terminals and the things works fine in an environment very stable and secure. Now the BIG problem ------------------- Recently I'm testing a new Thin Client solution (http://www.vortex86.com) to subsitute these PCs for something more "thin" and little. This Thin Client have a Vortex86 processor at 200Mhz and 128MB of RAM, and is a good solution in order to think to convert all the PCs into this very little Thin Client. To test this new Thin Client almost nothing was changed in the LTSP configuration, just the MAC address and the video configuration and resolution. The problem arises when unexpectedly the X-Forwarding feature hang the keyboard after 3 or 4 key-clicks. The mouse continues working (well at least it moves), but the keyboard does not respond, keyboard-leds are dead and the display freezed. If I remove the line "ssh -X user at linuxserver ....." and (manually) executes from the Linux server the OpenOffice program with the DISPLAY variable containing the Thin Client IP address (that is not using X-Forwarding nor OpenSSH at all), it works fine!!!. Moreover, if I executes from the Thin Client "X -query" in order to begin an XDM session (or KDM session), it works fine!!! That's mean that the problem is on X-Forwarding. But what is the cause for this strange behavior? Thanks in advance. -- Jordi Sanfeliu FIBRANET Network Services Provider http://www.fibranet.com
Jordi Sanfeliu wrote:> To test this new Thin Client almost nothing was changed in the LTSP > configuration, just the MAC address and the video configuration and > resolution. The problem arises when unexpectedly the X-Forwarding > feature hang the keyboard after 3 or 4 key-clicks. The mouse continues > working (well at least it moves), but the keyboard does not respond, > keyboard-leds are dead and the display freezed.That sounds like a hardware (or low-level OS problem).> If I remove the line "ssh -X user at linuxserver ....." and (manually) > executes from the Linux server the OpenOffice program with the DISPLAY > variable containing the Thin Client IP address (that is not using > X-Forwarding nor OpenSSH at all), it works fine!!!.Perhaps the extra load caused by the crypto pushes borderline hardware over the edge, or possibly uncovers some kind of race in the OS? Try running something to suck up all the CPU and see if your problems happen without ssh (I suggest "openssl aes-128-cbc -in /dev/zero -out /dev/null" with a bogus password). -- Darren Tucker (dtucker at zip.com.au) GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4 37C9 C982 80C7 8FF4 FA69 Good judgement comes with experience. Unfortunately, the experience usually comes from bad judgement.
Darren Tucker wrote:> > That sounds like a hardware (or low-level OS problem). >Maybe, but the linux kernel 2.4.24, XFree86 4.3.99 (4.4.0RC1) and all the other utilities does not report any problem.> > Perhaps the extra load caused by the crypto pushes borderline hardware > over the edge, or possibly uncovers some kind of race in the OS? > > Try running something to suck up all the CPU and see if your problems > happen without ssh (I suggest "openssl aes-128-cbc -in /dev/zero -out > /dev/null" with a bogus password). >Tried. I have downloaded from openssl.org its last version (0.9.7d) and compiled. Then it has been executed _during 3 hours_ on such hardware (Thin Client with Vortex86), using your suggestion reproduced above. Result. All works fine. After 3 hours I have pressed CTRL-C in order to stop the execution and the keyboard responds well as expected. No hardware freeze or keyboard hang. We will need to search the source of problem in other direction. I will try to disable the Compression during the X-Forwarding process ... -- Jordi Sanfeliu FIBRANET Network Services Provider http://www.fibranet.com