Looking at the source code this seems to be fixed in rdesktop version
1.6.0-2ubuntu2 available in Karmic at least.
** Changed in: rdesktop (Ubuntu)
Status: New = Fix Released
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rdesktop1.6 is unable to connect to windows 2008 servers
https://bugs.launchpad.net/bugs/499731
You received
It is fixed in Karmic, but not in Hardy, and Hardy is the current LTS.
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rdesktop1.6 is unable to connect to windows 2008 servers
https://bugs.launchpad.net/bugs/499731
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
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ubuntu-bugs
** Attachment added: 01_fix_ssl.patch
http://launchpadlibrarian.net/37119068/01_fix_ssl.patch
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rdesktop1.6 is unable to connect to windows 2008 servers
https://bugs.launchpad.net/bugs/499731
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to