On Thursday March 27, 2003, at 3PM, I plan to change the "alias" ftp.nevis.columbia.edu to point to hammurabi.nevis.columbia.edu instead of nevis1.nevis.columbia.edu. The new ftp server is already up and running; here is a sample link:

ftp://hammurabi.nevis.columbia.edu/pub/

I shall turn off the anonymous ftp server on nevis1 a few days after the switch, to give time for the new alias to propagate on the world's DNS servers.

Why is this being done?

There are three main reasons for this switch:

1. It's part of a general move of Nevis system services off of nevis1 and onto the Linux cluster.

2. FTP is one of the least secure communication protocols still in use on the Internet. On every Nevis computer that still has FTP services enabled, I see log messages indicating system crackers trying to break in, trying to search our FTP archives for illegal software, or trying to place illegal software on our systems for others to copy.

   I have encouraged everyone to use sftp or scp instead of FTP. As I install or upgrade new systems in the Nevis Linux cluster, I have not enabled FTP services unless a user specifically asks for it.

   However, we can't completely eliminate FTP at Nevis, at least not yet. For accessing files via a web browser, or for computer systems that don't yet support sftp, anonymous FTP may still be the best answer.

   So if we must have anonymous FTP services at Nevis, a more secure solution is to have a single box dedicated to this task, specially configured to be more secure than a typical server or workstation.

3. We're running out of disk space in the anonymous FTP directory on nevis1. We have to move those files to some new disk; it might as well be to a disk on a faster machine with more available storage.

How will this affect our work?

The short answer is: probably not at all.

As far as I know, I'm the only one using anonymous FTP on a regular basis to distribute files to people outside of Nevis. (This fact, plus the disk space issue mentioned above, may correctly lead you to the conclusion that I'm not being entirely altruistic in setting up this new FTP server.)

If one of your web pages had a link of the form:

ftp://nevis1.columbia.edu/pub/somefile.txt

it would have to be changed to:

ftp://ftp.nevis.columbia.edu/pub/somefile.txt

However, that's probably been done already, as part of the upgrade to the new web server.

If you've distributed instructions to anyone for anonymously FTPing a file from Nevis, you'll have to revise any reference to nevis1 in those instructions to ftp.nevis.columbia.edu.

Frequently-Asked Questions

• Does this mean that FTP will be turned off on nevis1?

  No. If you're user jsmith, you'll still be able to do something like this:

  > ftp nevis1.nevis.columbia.edu Connected to nevis1.nevis.columbia.edu. 220- Nevis Laboratories -- Unauthorized Access Prohibited 220 nevis1.nevis.columbia.edu FTP server ready. Name: jsmith 331 Password required for jsmith. Password: 230 User jsmith logged in. Remote system type is UNIX. Using binary mode to transfer files. ftp>

  What will be turned off is anonymous FTP, that is, the access to files via FTP that do not require an account on nevis1. A typical exchange with an anonymous FTP server goes like this:

  > ftp ftp.nevis.columbia.edu Connected to ftp.nevis.columbia.edu. 220 Nevis Laboratories -- Anonymous FTP -- Unauthorized Access Prohibited Name: anonymous 331 Guest login ok, type your name as password. Password: jsmith@nevis.columbia.edu 230 Login successful. Have fun. Remote system type is UNIX. Using binary mode to transfer files. ftp>

  In the latter case, you don't supply a user name and password to the FTP server -- but you don't get access to all the files on the machine, either. You only gain access to files in a special public area on the FTP server.

• I tried to login to the new FTP server with my account name, and got the message "This FTP server is anonymous only." What's the problem?

  This is not a problem. The anonymous FTP server does only one thing: anonymous FTP. No one can login to the machine directly.

  If you want to make files available via anonymous FTP, use the procedure described in this guide.

• I looked at the listing in ftp://hammurabi.nevis.columbia.edu/pub/, and saw a lot of old, obsolete files that I left there. Is it OK if I clean them up?

  Yes, please do so!

  Before I make the FTP server switch, you can make changes in the public FTP area by logging onto nevis1, and visting directory ~ftp/pub/. You can also makes changes from the Linux cluster, but you'll have to visit /a/file/usr2/local/ftp/pub/ (to learn why this works, see the page on automount.

  After I make the FTP server switch, you can just go to ~ftp/pub/ on either the cluster or on nevis1.

• I'm using a Windows machine, and I'm having trouble using FTP to transfer files to a Linux machine/

  This is answered in the general Frequently-Asked Questions page for the Linux cluster.

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