Well I tried to download freebsd iso and i issued the command:
--proxy-user=[username] --proxy-passwd=[password] -vO - |split -b 90m - bsd
But it showed the following error message:
Connecting to 22.214.171.124:3128... connected.
Proxy request sent, awaiting response... 403 Forbidden
09:41:12 ERROR 403: Forbidden.
Theproxy blocks http and ftp both. However it only checks the size of the file being downloaded at a time not the whole file size, that's where the trick can be played. Please suggest something. Obviously our sysadmin owns the proxy.