Simon Zambrovski

"One Cannot Not Communicate" – Watzlawick

The postbank uses firewalls with invalid set-up. All ICMP-Traffic is dropped. This causes problems while accessing the site over a Linux 2.4 Router with NAT (The problem background can be found in German here: http://portal.suse.de/sdb/de/2001/11/cg_pmtu2.html)

Basically, it is the handshaking of the packet size based on MTU of PPPoE by packets with DF-flag (Don’t fragment) set. This handshaking is based on special ICMP command.

Today I tried out Google Talk, another product extending the Google Empire. It works very fine and managed to communicate across the corporate boundaries with non-transparent HTTPS proxy.

This is a very helpfull feature in terms of a global avaliability. I continue to use Skype, because of its Skype-Out feature and hope that Google will extend its Talk or simply buy Skype…

Today I was suprised about the bad compatibility of the WebDav system component. I wanted to upload some data on an Linux Apache Web Server with installed Web-DAV module, with Authorization based on AuthType digest from my WindowsXP workstation.
In following I describe the activities needed for that simple operation:

  1. Opened “Network neighbourhood” added new Connection, entered a server name and directory.
  2. A dialog appered in order to provide the auth-information. Entered my username and my password.
  3. Same dialog apperead again, my username was replaced with servername\username
  4. Asked the system administrator => the webfolder doesn’t work with digest authorisation, please use another client
  5. Tried Eclipse Web-Dav integration, but forgot the trailing “/” in the directory name => Error : Bad request.
  6. Entered in google: webdav client windows.
  7. Took the first link: http://www.webdav.org/projects/
  8. Scrolled a little, selected “WebDav Explorer” and downloaded
  9. The zip-File contained of severeal batch files and a jar archive.
  10. Started the program => Couldn’t understand how to use it in 2 minutes, managed to copy one file, but not a group of files.
  11. Returned to google and selected the second link (FTP Client with WebDav support from bitkinex.com)
  12. Downloaded a trial version and installed it.
  13. A huge two-window application appeared on the screen. Managed to input the server data.
  14. Connected. Tried to copy files. => Errors during copy. The process took 2 minutes. Checked if the files were there => No files on server.
  15. Used server property (context pulldown-menu) to discover the dialog “Paths on server”
  16. Entered my directory, reconnected.
  17. Copied files and verified the existence => Files were there. The program is working only 30-days in a trial version.
  18. Went back to google and entered “windows commander webdav” in order to find a plug-in for “Total Commander”.
  19. Found a plugin and downloaded it and installed.
  20. Created a new connection but forgot the trailing “/” again. => Error : Bad Method.
  21. Analysed the log => TotalCMD tries to execute PROPFIND “/”.
  22. Downloaded the code of the plugin. Opened the plugin in Visual Studio.
  23. Found the corresponding place, on which the plugin calculates the path.
  24. Understood, that the trailing “/” is neede in the path
  25. Created a new connection with a trailing “/” after the directory name. => It worked fine, I could transfer files.
  26. Tried the same thing in Eclipse adding a trailing “/” to the path. => It worked too.

So my questions are:

  1. Is it that difficult to verify the trailing “/” in a tool?
  2. Why so many people supply so bad tools, that the extensive reading of manual is needed in order to find out how the program works?
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