Franz, 12345 from the "server side" looks like a 40 bit key (8 bits per character, multiplied by 5 characters). This would explain why it's working when you use that option. In order to be completely sure that it's not a 40 bit key, would you please re-create your server environment with a WEP-128 passphrase of something like '123456'? Thank you.
More information here: https://mail.gnome.org/archives/networkmanager- list/2007-December/msg00226.html ** Changed in: network-manager (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1032433 Title: Using WEP 128-bit Passphrase, Ad-hoc connection cannot be established Status in OEM Priority Project: New Status in OEM Priority Project precise series: New Status in “network-manager” package in Ubuntu: Incomplete Bug description: When setting up an ad-hoc wifi connection, if choose "WEP 128-bit Passphrase", the connection cannot be established. If choose "None" or "WEP 40/128-bit Key", it can be established successfully. Steps to reproduce: 1. Choose "Create new Wireless Network" in network applet 2. Choose "WEP 128-bit Passphrase" and create an ad-hoc connection 3. Use another computer to connect the same ad-hoc ESSID 4. The connection cannot be established To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1032433/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp