fetch – and how to use it behind a firewallfetch allows you to retrieve a file by supplying a URL (Uniform Resource Locator). It is very useful and powerful tool. It effectively automates an anonymous FTP session.
If you get the following message when you use fetch, then I suspect you are behind a firewall:
su-2.02# fetch ftp://<somefilename> fetch: ftp://<somefilename>: FTP error: fetch: Can't open data connection su-2.02#
If you are behind a firewall, you might want to try the -P option on the command line. This will force fetch to "use the passive mode of the FTP protocol. This is useful for crossing certain types of firewalls." [as quoted from man fetch].