Linux System Administrator's Survival Guide lsgxa.htm

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Appendix A


Linux FTP Sites and Newsgroups


If you have access to the Internet, either directly or through an online service provider such as CompuServe, Delphi, or America Online, you can access additional sources of Linux software and information. Two popular sources of Linux software and help are available, one through FTP and the other through Linux-specific USENET newsgroups.

If you don't have access to the Internet, you may still be able to get some of the information available through other sources, such as Bulletin Board Systems (BBSs) and CD-ROMs published by companies specializing in redistributing public domain material.

FTP Sites


FTP is a method of accessing remote systems and downloading files. It is quite easy to use and provides users who have Internet access with a fast method for updating their list of binaries.

For those without FTP access but who can use electronic mail through the Internet, the utility ftpmail can provide access to these FTP sites.

What Is FTP?


File Transfer Protocol (FTP) is one protocol in the TCP/IP family of protocols. TCP/IP is used extensively as the communications protocol of the Internet, as well as in many Local Area Networks (LANs). UNIX systems almost always use TCP/IP as their protocol.

FTP is used to transfer files between machines running TCP/IP. FTP-like programs are also available for some other protocols.

To use FTP, both ends of a connection must be running a program that provides FTP services. To download a file from a remote system, you must start your FTP software and instruct it to connect to the FTP software running on the remote machine.

The Internet has many FTP archive sites. These are machines that are set up to allow anyone to connect to them and download software. In some cases, there are FTP archive sites that mirror each other. A mirror site is one that maintains exactly the same software as another site, so you simply connect to the one that is easiest for you to access, and you have the same software available for downloading as if you had connected to the other site.

Usually, when you connect to a remote system, you must log in. This means that you must be a valid user, with a username and password for that remote machine. Because it is impossible to provide logins for everyone who wants to access a public archive, many systems use anonymous FTP. Anonymous FTP enables anyone to log into the system with the login name of guest or anonymous and either no password or the user's login name or e-mail address (used for auditing purposes only).

Connecting and Downloading Files with FTP


Using FTP to connect to a remote site is quite easy. Assuming that you have access to the Internet either directly or through a service provider, you must start FTP and provide the name of the remote system to which you want to connect. If you are directly connected to the Internet, the process is simple: you enter the ftp command with the name of the remote site: 


ftp sunsite.unc.edu

If you are using an online service, such as Delphi, you must access its Internet services menus and invoke FTP from that. Some online services enable you to enter the name of any FTP site at a prompt, whereas others have some menus that list all available sites. You may have to hunt through the online documentation for your service provider to find the correct procedure.

After you issue the ftp command, your system will attempt to connect to the remote machine. When it does (if the remote system allows FTP logins), the remote will prompt you for a user ID. If anonymous FTP is supported on the system, a message will usually tell you that. The following login is shown for the Linux FTP archive site sunsite.unc.edu: 


ftp sunsite.unc.edu

331 Guest login ok, send your complete e-mail address as password.

Enter username (default: anonymous): anonymous

Enter password [[email protected]]:

|FTP| Open

230- WELCOME to UNC and SUN's anonymous ftp server

230- University of North Carolina

230- Office FOR Information Technology

230- SunSITE.unc.edu

230 Guest login ok, access restrictions apply.

FTP>

After the login process is completed, you will see the prompt FTP>, indicating that the system is ready to accept commands. When you log in to some systems, you see a short message that might contain instructions for downloading files, any restrictions that are placed on you as an anonymous FTP user, or information about the location of useful files. For example, you might see messages like this one: 


To get a binary file, type: BINARY and then: GET "File.Name" newfilename

To get a text file, type: ASCII and then: GET "File.Name" newfilename

Names MUST match upper, lower case exactly. Use the "quotes" as shown.

To get a directory, type: DIR. To change directory, type: CD "Dir.Name"

To read a short text file, type: GET "File.Name" TT

For more, type HELP or see FAQ in gopher.

To quit, type EXIT or Control-Z.

230- If you email to [email protected] you will be sent help information

230- about how to use the different services sunsite provides.

230- We use the Wuarchive experimental ftpd. if you "get" <directory>.tar.Z

230- or <file>.Z it will compress and/or tar it on the fly. Using ".gz" instead

230- of ".Z" will use the GNU zip (/pub/gnu/gzip*) instead, a superior

230- compression method.

After you are connected to the remote system, you can use familiar Linux commands to display file contents and move around the directories. To display the contents of a directory, for example, use the command ls or the DOS equivalent DIR. To change to a subdirectory, use the cd command. To return to the parent directory (the one above the current directory), use the command cdup or cd ... FTP has no keyboard shortcuts, so you have to type in the name of files or directories in their entirety.

When you have moved through the directories and have found a file you want to move back to your home system, use the get command: 


get "file1.txt"

The commands get (download) and put (upload) are relative to your home machine. You are telling your system to get a file from the remote location and put it on your local machine, or to put a file from your local machine onto the remote machine. This is the exact opposite of another commonly used TCP/IP protocol, telnet, which has everything relative to the remote machine. It is important to remember which command moves in which direction, or you could overwrite files accidentally.

The quotation marks around the filename are optional for most versions of FTP, but they do provide specific characters to the remote version (preventing shell expansion), so you should use the quotation marks to avoid mistakes. FTP provides two modes of file transfer: ASCII and binary. Some systems will automatically switch between the two, but it is a good idea to set the mode manually to ensure that you don't waste time. To set FTP in binary transfer mode (for any executable file), type the following command: 


binary

You can toggle back to ASCII mode with the command ASCII. Because you will most likely be checking remote sites for new binaries or libraries of source code, it is a good idea to use binary mode for most transfers. If you transfer a binary file in ASCII mode, it will not be executable (or understandable) on your system. ASCII mode includes only the valid ASCII characters and not the Ctrl-key sequences used within binaries. Transferring an ASCII file in binary mode does not affect the contents, although spurious noise may cause a problem in rare instances.

When you issue a get command, the remote system will transfer data to your local machine and display a status message when it is finished. There is no indication of progress when a large file is being transferred, so be patient. 


FTP> get "file1.txt"

200 PORT command successful.

150 BINARY data connection for FILE1.TXT (27534 bytes)

226 BINARY Transfer complete.

27534 bytes received in 2.35 seconds (12 Kbytes/s).

To quit FTP, type the command quit or exit. Either will close your session on the remote machine, then terminate FTP on your local machine.

Using ftpmail


If you don't have access to a remote site through FTP, all is not lost. If you have electronic mail, you can still get files transferred to you. Some online systems allow Internet mail to be sent and received but do not allow direct access to FTP. Similarly, some Internet service providers offer UUCP accounts that do not allow direct connection but do provide e-mail. To get to FTP sites and transfer files, you use the ftpmail utility.

The site mentioned earlier, sunsite.unc.edu, is a major Linux archive site that supports ftpmail. All of the sites listed in this Appendix as Linux FTP sites also support ftpmail. To find out how to use ftpmail, send an e-mail message to the login ftpmail at one of the sites, such as [email protected], and have the body of the message contain only one word: help.

By return mail, the ftpmail utility will send instructions for using the service. Essentially, you send the body of the ftp commands you want executed in a mail message, so you could get back a directory listing of the Linux directory in a mail message with this text: 


open sunsite.unc.edu

cd /pub/Linux

ls

quit

You could transfer a file back through e-mail with a similar mail message: 


open sunsite.unc.edu

cd /pub/Linux

binary

get README

quit

The ftpmail system is relatively slow, as you must wait for the e-mail to make its way to the target machine and be processed by the remote, then for the return message to make its way back to you. It does provide a useful access method for those without FTP connections, though, and a relatively easy way to check the contents of the Linux directories on several machines.

Linux FTP Archive Sites


The list of Linux FTP archive sites changes slowly, but the sites listed in Table A.1 were all valid and reachable when this book was written. Many of these sites are mirror sites, providing exactly the same contents.

To find the site nearest you, use the country identifier at the end of the site name (uk=United Kingdom, fr=France, and so on). Most versions of FTP allow either the machine name or the IP address to be used, but if the name cannot be resolved by the local Internet gateway, the IP address is the best addressing method.

Table A.1. Linux FTP archive sites.

Site name IP Address Directory
tsx-11.mit.edu 18.172.1.2 /pub/linux
sunsite.unc.edu 152.2.22.81 /pub/Linux
nic.funet.fi(Finland) 128.214.6.100 /pub/OS/Linux
ftp.mcc.ac.uk(U.K.) 130.88.200.7 /pub/linux
fgbl.fgb.mw.tu-muenchen.de(Denmark) 129.187.200.1 /pub/linux
ftp.infdrrnatik.twmuenchen.de(Denmark) 131.159.0.110 /pub/Linux
ftp.dfv.rwth-aachen.de(Denmark) 137.226.4.105 /pub/linux
ftp.informatik.rwth-aachen.de(Denmark) 137.226.112.172 /pub/Linux
ftp.ibp.fr(France) 132.227.60.2 /pub/linux
kirk.bu.oz.au(Australia) 131.244.1.1 /pub/OS/Linux
ftp.uu.net 137.39.1.9 /systems/unix/linux
wuarchive.wustl.edu 128.252.135.4 /systems/linux
ftp.win.tue.nl 131.155.70.100 /pub/linux
ftp.stack.urc.tue.nl 131.155.2.71 /pub/linux
ftp.ibr.cs.tu-bs.de 134.169.34.15 /pub/os/linux
ftp.denet.dk 129.142.6.74 /pub/OS/linux

The primary home sites for the Linux archives are tsx-11.mit.edu, sunsite.unc.edu, and nic.funet.fi. Home sites are where most of the new software loads begin. The majority of sites in Table A.1 mirror one of these three sites.

Bulletin Boards


There are literally hundreds of Bulletin Board Systems (BBSs) across the world that offer Linux software. Some download new releases on a regular basis from the FTP home sites, whereas others rely on the users of the BBS to update the software.

A complete list of BBSs with Linux software available would be too lengthy (as well as out-of-date almost immediately) to include here. Zane Healy maintains a complete list of BBSs offering Linux material. To obtain the list, send e-mail requesting the Linux list to [email protected].

If you don't have access to e-mail, try posting messages on a few local bulletin board systems asking for local sites that offer Linux software, or ask someone with Internet access to post e-mail for you.

LINUX-related BBSs


Zane Healy ([email protected]) maintains this list. If you know of or run a BBS that provides Linux software but isn't on this list, you should get in touch with him.

You can also get an up-to-date list on BBSs from tsx-11.mit.eduin the /pub/linux/docs/bbs.list file. The following lists were up-to-date at the time this book went to print.

United States BBSs

Here is a list of some of the BBSs in the United States that carry Linux or information about Linux:


Outside of the United States

If you live outside the US, you can get information about Linux from these BBSs:


USENET Newsgroups


USENET is a collection of discussion groups (called newsgroups) that is available to Internet users. There are over 9,000 newsgroups with over 100MB of traffic posted every single day. Of all of these newsgroups (which cover every conceivable topic), several are dedicated to Linux.

You can access USENET newsgroups through special software called a newsreader if you have access to a site that downloads the newsgroups on a regular basis. Alternatively, most online services such as CompuServe, America Online, and Delphi also offer access to USENET. Some BBSs also provide limited access to newsgroups.

USENET newsgroups fall into three categories: primary newsgroups, which are readily available to all USENET users; local newsgroups with a limited distribution; and alternate newsgroups that may not be handled by all news servers. The primary newsgroups of interest to Linux users are
comp.os.linux.admin Installing and administering Linux systems
comp.os.linux.advocacy Proponents of the Linux system
comp.os.linux.announce Announcements important to the Linux community (moderated)
comp.os.linux.answers Questions and answers to problems
comp.os.linux.development Ongoing work on Linux
comp.os.linux.development.apps Ongoing work on Linux applications
comp.os.linux.development.system Ongoing work on the Linux operating system
comp.os.linux.hardware Issues with Linux and hardware
comp.os.linux.help Questions and advice about Linux
comp.os.linux.misc Linux-specific topics not covered by other groups
comp.os.linux.networking Making the Linux system network properly
comp.os.linux.setup Setup and installation problems with Linux

These newsgroups should be available at all USENET sites unless the system administrator filters them out for some reason.

The other newsgroups tend to change frequently, primarily because they are either regional or populated with highly opinionated users who may lose interest after a while. The .alt (alternate) newsgroups are particularly bad for this. Only one .alt newsgroups was in operation when this book was written:

alt.uu.comp.os.linux.questions

There are also regional newsgroups that usually are not widely distributed, or that have specific issues which may be in a language other than English. Some sample regional newsgroups carried by USENET are:

If you do have access to USENET newsgroups, it is advisable to regularly scan the newsgroup additions and deletions to check for new Linux newsgroups or existing groups that have folded. Most online services that provide access to USENET maintain lists of all active newsgroups that can be searched quickly.

The traffic on most of these Linux newsgroups deals with problems and issues people have when installing, configuring, or using the operating system. Usually, a lot of valuable information is passing through the newsgroups, so check them regularly. The most interesting messages that deal with a specific subject (called threads) are collected and stored for access through an FTP site.

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