Cisco ASA – Java RDP Error – Connection Exception Wrong modulus size! Expected64 +8got:264

KB ID 0000452 Dtd 13/05/11

Problem

Seen while attempting to connect to to a Windows machine via the RDP plug in on a Cisco ASA firewall.

Connection Exception Wrong modulus size! Expected64 +8got:264

Error:
properJavaRDP error
Connection Exception Wrong modulus size! Expected64 +8got:264

Solution

1. I’ve seen some posts indicating that this can be caused by the version of Java that’s installed, however in my case that was NOT the problem.

2. Connect to the ASDM of the ASA firewall > Configuration > Clientless SSL VPN Access > Portal > Client Server Plug-ins. Ensure your RDP plug in is up to date, download and import the latest one (Cisco CCO account and valid support agreement required).


Note: At time of writing the latest is rdp2-plugin.090211.jar (released 14/08/09).

rdp plugin ASA

3. Ensure that the bookmark you are using is set to use rdp2 (not rdp). Under Portal > Bookmarks > Your bookmark list > Edit.

ASA rdp2 plugin

4. Your RDP session should now connect.

RDP connected

 

Related Articles, References, Credits, or External Links

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Author: Migrated

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