EX SSL-VPN: FTP Connection Drops During Transfer Through Connect Tunnel and Blue Coat Client Proxy

Problem Definition:

SonicWall support has found an issue where a backend FTP connection may break while downloading large files using Blue Coat Client Proxy Accelerator through Connect Tunnel. The file transfer proceeds normally until it is 40-50 percent complete, and then the FTP connection breaks. The tunnel connection still remains active and users can get to other resources normally.

Resolution

This issue can be resolved at the Blue Coat Proxy device by following the steps below:

1. Go to the Blue Coat CLI Prompt using SSH or Console.
2. Go into enable mode:
   conf t
3. Run the following command to disable RFC 1323:
   tcp-ip rfc-1323 disable

More information and history about this workaround can be found at this link: http://forums.bluecoat.com/viewtopic.php?f=1&t=7031&p=22933