On 04/25/2013 08:08 AM, Alex Rousskov wrote: > Dave, it looks like FileZilla did not receive FTP server Hello from > Squid. I suggest that you take packet captures before and after Squid, > to see whether Squid itself has received FTP server Hello from the FTP > server. If Squid connected to the FTP server but received nothing, then > the problem is on the FTP server side. Otherwise, the problem may be > with Squid. I forgot to mention that even if you succeed with making CONNECT work, it will not help you with ICAP inspections because Squid will only send CONNECT request to your ICAP server and not the FTP traffic that happens inside the HTTP CONNECT tunnel. If you must use FileZilla, and FileZilla does not support sending HTTP requests with ftp://urls to HTTP proxies (instead of using CONNECT tunnels with raw FTP inside), then you must use an FTP proxy that supports ICAP, not an HTTP proxy. Our FTP gateway project adds that functionality to Squid. It is not ready for production use, but simple FTP transactions are supported and code is available: http://wiki.squid-cache.org/Features/FtpGateway HTH, Alex.