readme.4.1

Linux下的socks的程序源程序,用于socks的代理服务

This is CSTC 4.1 release of SOCKS, a package that allows Unix hosts
behind a firewall to gain full access to the internet without requiring
direct IP reachability. It does require a SOCKS server program being
run on a hosts that can communicate directly to hosts behind the firewall
as well as hosts on the Internet at large.  It is based on the original
SOCKS written by David Koblas <[e-mail]>.

The package includes full source for the SOCKS server and SOCKSified
client programs of finger, ftp, telnet, and whois. Other SOCKSified
clients such as xgopher (ver. 1.3.1) and Mosaic (ver. 2.0) can be
found on ftp.nec.com, in directory /pub/security/socks.cstc. (On
WWW, the URL is file://ftp.nec.com/pub/security/socks.cstc ) Mosaic 2.1
as distributed by NCSA already contains the SOCKSification patch in its
source, which is available from ftp.ncsa.uiuc.edu, in /Mosaic/Mosaic-source.

This release is known to run on the following Unix platforms:

SunOS 4.1.x ([e-mail])
Irix 4.0.x ([e-mail])
Ultrix 4.3 ([e-mail], [e-mail])
HP-UX 9.0x ([e-mail], [e-mail], [e-mail])
AIX 3.2.x ([e-mail], [e-mail])
Interactive Systems Unix ([e-mail])
Alpha OSF 1.3 ([e-mail], [e-mail], [e-mail])
Solaris 2.2 ([e-mail])
NetBSD 0.9 ([e-mail])
UnixWare ([e-mail])
Linux 0.99pl13 ([e-mail], [e-mail])

-------------------- MAJOR CHANGES SINCE 4.0

1)You now have the option to build 'sockd' to run on a multi-homed
  host by defining the symbol 'MULTIHOMED_SERVER' in include/socks.h.
  A multi-homed server requires another control file /etc/sockd.route
  to tell it which of its network interfaces it should use for communicating
  with which networks or hosts. For example:

# Use interface 120.10.1.5 for host 100.1.2.3
120.10.1.5	100.1.2.3 255.255.255.255
# Use interface 120.10.2.10 for hosts in network 193.10.2
120.10.2.10	193.10.2.0 255.255.255.0
# Use interface 198.1.1.1 for all other connections
198.1.1.1	0.0.0.0 0.0.0.0

  For a typical dual-homed server, all you need is a single line:

outside_interface	0.0.0.0 0.0.0.0

  where 'outside_interface' should be the IP address of the network
  interface going outside of your firewall.

  test_sockd_conf has been updated so that it also checks the new control
  file and tells you which interface will be used.
 
2)You can now build 'versatile' clients, which uses SOCKS server(s)
  to reach outside of your firewall but connects directly to hosts
  within the firewall. So, for example, you can save away your regular
  ftp program and replace it with the versatile SOCKS ftp client (rftp).
  You have to be careful with 'finger' though and make sure that the
  macro 'ORIG_FINGER' is properly defined in include/socks.h.

  All versatile clients use the file /etc/socks.conf to decide whether
  a connection should be denied, done directly, or done indirectly through
  SOCKS server at one or more hosts. For example:

# Deny ftp and telnet access by baduser
deny	*=baduser	0.0.0.0 0.0.0.0	eq ftp: mail -s 'ftp by baduser' root
deny	*=baduser	0.0.0.0 0.0.0.0	eq telnet: mail -s 'telnet by baduser' root
# Be sure to include the next line for localhost!
direct	127.0.0.1	255.255.255.255
# Use direct connection to all hosts in network 120.10
direct	120.10.0.0 255.255.0.0
# Use the defaiult SOCKS server to connect to host 13.13.13.13
sockd			13.13.13.13 255.255.255.255
# For other connections, try SOCKS servers at 120.10.2.3, 120.10.50.1,
# in that order
sockd	@=120.10.2.3,120.10.50.1	0.0.0.0 0.0.0.0

3)As you may have already noticed, the interpretation of address masks
  are changed. 1's in a mask now denote the bit positions that matter
  while 0's denote the don't-care bit positions. In other words, they
  are now interpreted the same way as IP netmasks. This holds true not
  only for the two new control files mentioned above, but also for 
  /etc/sockd.conf. A new program 'flip_cfmasks' is provided in the sockd
  subdirectory to convert the old format to the new one. Just do

flip_cfmasks /etc/sockd.conf sockd.conf.flip

  check the output file sockd.conf.flip to see if all is well (with any
  luck it should be) and then use that with the new server.

4)An optional getpass() is provided to communicate with systems that
  may require longer password (> 8 characters). This is for regular
  passwords. As in 4.0, "passwords" for anonymous ftp can be longer than
  8 characters even without using the optional getpass().

5)Termination of a TCP session is now also logged on the SOCKS server,
  including the number of bytes transported in either direction.

6)An compile time option is provided to make ftp (rftp) log the name
  of every file transferred.

7)The man pages are substantially revamped.

All 4.1 clients work with all 4.0 and 4.1 servers. 4.0 clients work
with single-homed 4.1 servers but NOT with 4.1 multi-homed servers.
'sockd -ver' tells you not only the version number but also whether
it is single- or multi-homed.

Please see below for the procedure for building and testing.
Remember that the names of the control files are all configurable
in include/socks.h. It will probably greatly reduce your frustration
while you are flipping between the old and the new versions if you
uses different file names for the new version. 


There is now a mailing list devoted to issues related
to SOCKS. To join the list, please send an email subscription request
with your email address to [e-mail].

Finally, I want to thanks all the people who have helped in making
and shaping this release. I certainly remember discussions and
contributions from the following, please forgive me (and remind me)
if I inadvertently leave your name off the list.

  [e-mail] (Brandon.Butterworth), [e-mail]
  (A. Bryan Curnutt), Ian Dunkin <[e-mail]>,
  [e-mail], Cornell Kinderknecht
  <[e-mail]>, [e-mail] (John W. Kupec),
  [e-mail] (jon r. luini), [e-mail] (Alain Mellan),
  Craig Metz <[e-mail]>, [e-mail]
  (Skip Montanaro), [e-mail] (Heinz Naef), [e-mail]
  (Rob Nagler), "Jason Ornstein" <[e-mail]>, [e-mail]
  (Garry M. Paxinos), [e-mail] (Michael Pechner), [e-mail]
  (Keenan Royle), [e-mail] (Ken Shackelford), Anthony
  Shipman <[e-mail]>, Rich Schultz <[e-mail]>,
  [e-mail] (Win Treese), [e-mail] (Paul Vickers),
  [e-mail] (David Vincenzetti), posc![e-mail]
  (David Waddell)

	Ying-Da Lee	[phone]	[phone] (FAX)
	Principal Member, Technical Staff
	NEC Systems Laboratory, C&C Software Technology Center /
	NEC USA, Corporate Network Administration Division
	[e-mail]
====================================================================

Please read the file 'COPYRIGHTS' before you proceed further.

In the following section, by 'top directory' we mean the top
directory of the SOCKS package, i.e., the directory you are
in right now. Ignore statements about rtelnet, rxgopher, and
rxmosaic if you are not building them.

-------------------------------------------------------------

HOW TO BUILD THE PROGRAMS

1. Check and modify the following files to suit your systems:

	Makefile
	include/socks.h

   Be sure that the macro 'SOCKS_DEFAULT_SERVER' in include/sosks.h
   is set correctly to the host that will be running the proxy server
   for your site.  Although this can be overridden at run time with
   environment variable SOCKS_SERVER, it is a lot simpler if you put
   in the right name at compile time. Also be sure to uncomment and set
   the macro 'SOCKS_DEFAULT_NS' in the same file if yor client machines
   normally cann't do DNS resolution for outside hosts.

   Be sure that the macros 'ORIG_FINGER' and 'MULTIHOMED_SERVER' in
   include/socks.h are set correctly.

   In most cases, you should have no needs to modify the Makefiles
   in the subdirectories. But if you run into problems, you may
   have to look into modifying

	sockd/Makefile
	libident/Makefile
	lib/Makefile
	rfinger/Makefile
	rftp/Makefile
	rtelnet/Makefile

   If your system is not among those included in the top Makefile,
   then you may also have to construct an entry for your system
   in the file rtelnet/Config.local.

2. cd to the top directory and issue 'make' command.  It's a good
   idea to direct stdout and stderr to a file so that you can
   see what's being done afterwards. There will be a few warning
   messages which you can ignore. This builds the server as well
   as all the clients.

   If you only want to build the server (and the program for testing
   your sever configuration file, AND THE PROGRAM FOR CONVERTING THE
   FILE TO THE NEW FORMAT), use comannd 'make server' instead.
   Use command 'make clients' to build only the client programs. You
   can also build the individual clients using 'make RFINGER',
   'make RFTP', and 'make RTELNET', all from the top directory.

3. All the man pages (except for libident) are in directory doc.
   You are encouraged to print them out and read them before proceeding
   to the next part.

-------------------------------------------------------------

HOW TO INSTALL THE SERVER

1. Become superuser on the proxy server host for your site. 

2. cd to the top directory and issue 'make install.server'.
   This installs programs sockd and test_sockd_conf as well
   as the man pages for them.

3. Add the line
socks	1080/tcp
   to file /etc/services. It would be nice also to include
gopher	70/tcp
WWW	80/tcp
   in the file if you don't already have them.

4. Add the line
socks	stream	tcp	nowait	nobody	/usr/etc/sockd	sockd
   to file /etc/inetd.conf. Use the actual path where sockd
   is installed if not in /usr/etc. If you want to make use of
   identd on your client machines when it is available, use
socks	stream	tcp	nowait	nobody	/usr/etc/sockd	sockd -i
   If you want to REQUIRE identd be run on your client machines,
   use
socks	stream	tcp	nowait	nobody	/usr/etc/sockd	sockd -I
   Running sockd with -I will reject all requests from hosts that
   do not run identd.

5. Set up access control with file /etc/sockd.conf. You have to
   read the man pages for sockd, sockd.conf, and test_sockd_conf
   for the details.
   For a quick test, you can use these four lines in the file: (Replace
   'client_IP' with the IP address of the host on which you will be
   testing the client programs.)
permit	client_IP   255.255.255.255
# One LONG line follows:
deny	0.0.0.0 0.0.0.0 : /usr/ucb/finger @%A | /usr/ucb/mail -s 'SOCKD: rejected -- from %u@%A to host %Z (service %S)' root
# Another LONG line:
#BAD_ID: /usr/ucb/finger @%A | /usr/ucb/mail -s '%U pretends to be %u on host %A' root@%A root
# Last line:
#NO_IDENTD: /usr/ucb/mail -s 'Please run identd on %A' %u@%A root@%A
   This is essentially the contents of file sockd/sockd.conf.sample.
   *** NOTE *** The meanings of 1's and 0's in address masks are
   reversed from previous versions. If you already have a working
   /etc/sockd.conf with an earlier version, use the program
   sockd/flip_cfmasks to produce one for the new version.

6. If the server host is multi-homed and you built sockd with the
   macro MULTIHOMED_SERVER in include/socks.h defined, you must
   also supply the file /etc/sockd.route. For a typical dual-homed
   server, this can simply be a one-liner:
out_interface	0.0.0.0 0.0.0.0
   where out_interface is the IP address of the server's network
   interface leading to the outside world. The format for lines
   in this file should be
# comments
Interface_addr	dst_addr dst_mask

   Read the man page on sockd.route !!!

7. Run a few tests using program test_sockd_conf to make sure you
   have the configuration file set up correctly. On a multi-homed
   server, the program also tests /etc/sockd.route and shows which
   interface is to be used.

8. Send a SIGHUP signal to the running inetd process so that it will
   use the new configuration. You may also have to do other things to
   accommodate syslog facility.  Read the man pages.

-------------------------------------------------------------

HOW TO TEST THE CLIENT PROGRAMS

   NOTE: Build and install identd on your client hosts first. This is
   required if you run sockd with -I option. It is a good idea anyway.

   Set up the file /etc/socks.conf on the client host. Lines in this
   file should be of the form
# comments
deny [*=userlist] dst_addr dst_mask [op port]
direct [*=userlist] dst_addr dst_mask [op port]
sockd [@=serverlist] [*=userlist] dst_addr dst_mask [op port]
   Fields in square brackets are optional. The optional @=serverlist
   field with a 'sockd' line specifies the list of SOCKS servers
   the client should try (in the given order) instead of the default
   SOCKS server.  If the @=serverlist part is omitted, then the default
   SOCKS server is used. Commas are used in the userlist and serverlist
   as separators, no white spaces are allowed.

   Read the man page on socks.conf !!!

   On a client host (for testing purpose, this can be the same as
   the proxy server), the clients rfinger, rwhois, rftp, and rtelnet,
   can be tried out without any additional setup on the
   client host once the server is running. They should behave like
   finger, whois, ftp, and telnet, respectively. rftp DOES
   echo your password IF you are using 'anonymous' as the log-in name.

   Quite a lot of details of operations of both the clients and the
   server are logged. Checking the contents of the log files may be
   helpful when you run into problems. You should try using these
   clients to connect to both inside and outside hosts and check the
   log messages to see whether the correct ways are used.

-------------------------------------------------------------

HOW TO INSTALL CLIENT PROGRAMS

1. Become superuser on the client host.

2. cd to the top directory, then issue the command 'make install.clients'.
   This installs rfinger, rwhois, rftp, rtelnet, and
   their man pages.

3. Rename your regular 'finger', 'whois', 'ftp', and 'telnet'
   to something else. The new name for the 'finger' program
   must be EXACTLY what you used for defining the macro ORIG_FINGER in
   include/socks.h. Then either rename the SOCKS clients or use symbolic
   links for them. For example, if you have installed the clients in
   directory /usr/local/bin and your regular 'finger', 'whois', 'ftp',
   and 'telnet' were in /usr/ucb, then you should do
ln -s /usr/local/bin/rfinger /usr/ucb/finger
ln -s /usr/local/bin/rftp /usr/ucb/ftp
ln -s /usr/local/bin/rhwois /usr/ucb/whois
ln -s /usr/local/bin/rtelnet /usr/ucb/telnet