My work allows the downloading of ISO images for work related projects. However the proxy we use has issues when downloading from FTP sites. I should also mention that downloading large files over http through this proxy is not ideal. It "caches" the whole file to the proxy before it sends it on to your download client. You lose resume support, and it often stops transferring files.
One thing I noticed though is that port 22 (SSH) doesn't have any proxy or firewall restrictions. My plan is to download any ISOs I require through a SFTP server, except I can't find any.
Are there any public SFTP servers that host Linux and/or FreeBSD ISOs?