|Nevis FTP Guide||
FTP ("File Transfer Protocol") is the program used to transfer files between computer systems. If you want to learn how to use the ftp command, type man ftp at the UNIX command prompt.
Before you use ftp, remember that it is insecure. If you type in your password to access files, the password may be "sniffed" across the network. Please consider using sftp or scp instead.
If you're here looking for help on transferring files between the Linux cluster and a Windows computer, see the FAQ.
If you have an account on the Nevis Linux cluster, you will be able to use sftp or scp to get any file from, and transfer any file to, any directory to which you'd normally have access if you were logged on. ftp is not enabled for every machine in the Linux cluster, unless a user specifically requests it; this is to discourage the use of ftp unless it's absolutely necessary.
If someone does not have an account on a system at Nevis, they can can get files from ftp.nevis.columbia.edu, and only through the mechanism of "anonymous" ftp. The remainder of this web page describes the issues that involve using anonymous FTP.
|How to make your files available via anonymous FTP|
If you want to make files available to users on other computer systems, you must use a special area that has been set aside for files to be accessed via ftp. This area is ~ftp/pub. (This area is physically located on the machine hammurabi.nevis.columbia.edu, but this has been mapped to ~ftp/pub on our machines.) All users with an account on the Linux cluster can place files in this area for public access.
Important: Any files you put into this area can be seen by the entire planet. If you want to restrict access to a file to specific people or institutions, the best way is to set up a directory via the Web at Nevis and protect the directory with a web-based password. Do not assume that no one will look at files in the FTP area just because you haven't told anyone about them; we have learned that this is not true.
Another important security tip: Do not create any folder in the FTP area with world-write permission. If you do, hackers will find it and use it to store files. This is not merely a possibility, this is a certainty!
You should also remove files from this area when you don't want them seen by the entire planet anymore. Web robots and system crackers continuously probe files available via anonymous ftp, looking for anything that appears interesting. Anything you put into ~ftp/pub is for public consumption; web search engines such as Google may assume that is it current, whether it's 15-year-old scientific results or love letters.
It is strongly recommended that you impose some directory structure on the files you place in this area. ~ftp/pub is a public area, and it is shared with everyone else at Nevis. If space becomes tight the files in this area may be randomly deleted. A basic rule of thumb: if a systems administrator can remember the purpose of the file, then it won't be deleted. So:
Although there's more than 10G available in ~ftp/pub, please don't use it to make massive DSTs available to other institutions. Although networks are becoming faster, it can still strain network resources to transfer huge files over the Internet. Maybe it would be simpler to copy the files to some form of physical media and mail them to other institutions.
|How to get files from the FTP server|
If you don't have an account on at Nevis, you can access the files in the FTP area via anonymous ftp.
331 Guest login ok, type your name as password.
ftp> cd pub/collab/data
The user can copy files via the get command.
|Putting files on the server via anonymous FTP|
This is no longer allowed. System crackers used it as means of distributing illegal files, and so this facility was turned off.
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