Department of Engineering

ftp

ftp is a Unix program that copies files between machines using the File Transfer Protocol. On non-mainstream machines like Macs, similar functionality is provided by fetch, etc. To access a remote machine you need to know an ID and password. Many remote machines provide an "anonymous" ftp service where the ID is "ftp" or "anonymous" and the password doesn't matter (but by convention the user's email address is normally used). WWW browsers can be used to get files from anonymous ftp sites.

FTP is a 2-way service - in principle you can copy files to and from your local machine. Also it keeps a connection open between the machines during a session, which contrasts with the way HTTP (WWW) operations work. Neither of these features assist security. The problems that you may encounter are likely to be related to security issues -

• How do I make a file of mine available at CUED via anonymous ftp? - Read about ftppub (type man ftppub).
• ftp isn't working properly when I access machines outside CUED - By default new CUED machines are set up so that they have restricted access to the outside world. Existing machines' IP addresses are gradually being changed so that they have restricted access too. This makes our machines more secure, but it also means that WWW access has to go via our proxy-server, and that ftp has to be done in a different way too. So try the following options in the given order until something works.
  • use a web browser, correctly configured to use CUED's cache/proxy
  • if you're using a Unix machine get the system administrator to install an ftp client that does passive mode by default (see /usr/src/local/network/ftp).
  • if your ftp client supports it, do "ftp -p machine" (passive mode)
  • Use the ftp.eng.cam.ac.uk machine on the Teaching System - i.e. log into it and do your ftp commands from there.
• Does the Teaching System have "secure ftp" (sftp)? - Yes, though note that many remote hosts don't support yet it.