_ RU.UNIX (2:5077/15.22) _____________________________________________ RU.UNIX _
From : serge terekhov 2:5000/44 Fri 19 Sep 97 16:02
Subj : SOCKS, was: SCO UNIX SVR5!
________________________________________________________________________________
On Sep 18 20:38, 1997, Ruslan Zalata of 2:5077/7 wrote:
RZ> Люди, а это такое эти "носки" (socks) ? Уже все мозги ими пpопилили, так
RZ> хоть бы pаскpыли секpетную сущность оных ? :-)
[SOCKS FAQ]
Question List (Last updated 08-15-96):
1. What is SOCKS?
2. How is Socks5 different from Socks4?
3. Is Socks5 interoperable with Socks4?
4. Where can I get SOCKS?
5. Are there any SOCKS related mailing lists?
6. Can I use SOCKS with Windows?
7. Can I use SOCKS with a Mac?
8. What do I have to do to modify programs to use
SOCKS?
9. Does SOCKS handle UDP?
10. How does SOCKS interact with DNS?
11. What is a single-homed and multi-homed firewall?
12. Is there an RFC for SOCKS?
13. What does SOCKS stand for?
14. Why does the password echo when I run rftp?
15. How do you traverse multiple firewalls (socksified
SOCKS server?)
16. Why do I see "inetd[]: socks/tcp server failing
(looping)" in my logs?
1. What is SOCKS?
SOCKS is a networking proxy mechanism that enables hosts on one
side of SOCKS server to gain full access to hosts in the other side
of the SOCKS server without requiring direct IP reachability. It
works by redirecting connection requests from hosts on one side to
hosts on the other side to a SOCKS server, who authenticates and
authorizes the requests, establishes a proxy connection and passes
data back and forth. It has been typically used as a network
firewall which enables hosts behind a SOCKS server to gain full
access to the Internet while preventing unauthorized access from
the Internet to the internal hosts.
There are two major versions of SOCKS, Socks4 and Socks5. David
Koblas is the original author.
More information about SOCKS can be found at
http://www.socks.nec.com/.
2. How is Socks5 different from Socks4?
The main differences between Socks5 and Socks4 are:
o Socks4 doesn't support authentication while Socks5 has a
built-in mechanism to support a variety of authentication methods.
o Socks4 doesn't support UDP proxy while Socks5 does.
See Introduction to SOCKS( http://www.socks.nec.com/introduction.html).
3. Is Socks5 compatible with Socks4?
The Socks5 protocol doesn't include any provision for supporting
the Socks4 protocol. However, it is a simple matter of
implementation. The Socks5 implementation from NEC does support the
Socks4 protocol. The server supports both V5 and V4 clients and can
communicate with other V5 and V4 servers.
4. Where can I get SOCKS?
Both Socks4 and Socks5 sources are available via http from
http://www.socks.nec.com/. They are also available via anonymous
ftp from ftp://ftp.nec.com:/pub/socks/.
Both packages include basic clients for telnet, ftp, finger, and
whois. In addition, NEC's Socks5 implementation includes archie,
ping, and traceroute.
Several other clients are available in the same directory at
ftp.nec.com as well as in http://www.socks.nec.com/
HP provides an internal implementation of SOCKS. It is available
from ftp://ftp.cup.hp.com/dist/socks/socks.tar.gz
Also, there are many commercial products that have built-in
support of SOCKS protocols.
5. Are there any SOCKS related mailing lists?
Yes, there are three SOCKS related mailing lists; the original
socks, Socks5, and sockscap. To join the SOCKS mailing list, send
email to majordomo@socks.nec.com with no subject line and a one
line body:
subscribe <mailing-list> <your@email.address>
Correspond with members of the list by sending e-mail to:
<mailing-list>@socks.nec.com
All three mailing lists are archived at http://www.socks.nec.com/
6. Can I use SOCKS with Windows?
Yes, NEC provides a WindowsNT version of Socks5 server. It is
available from http://www.socks.nec.com/.
There are a number of Winsock DLL extensions that enable WinSock
based applications to use SOCKS.
o SocksCap from NEC
o AutoSOCKS from Aventail
o Hummingbird's SOCKS Client from Hummingbird
There are also SOCKSified Winsock Stacks such as Peter Tattam's
SOCKSified Trumpet Winsock (currently in beta).
http://www.trumpet.com.au/wsk/winsock.htm.
In addition, many commercial WinSock applications support SOCKS
protocol.
8. What do I have to do to modify programs to use SOCKS?
The specific details of SOCKSification can be found at
http://www.socks.nec.com/how2socksify.html. Basically, you need to
recompile the sources with a few pre-processor directives to
intercept the regular calls to things like bind(). The Socks5
library can SOCKSify both TCP and UDP applications while the Socks4
library can only SOCKSify TCP based programs.
The Socks5 package from NEC includes some UNIX Socks5 client
shared libraries that can dynamically SOCKSify programs without
modifying nor recompiling them. Details can be found at
http://www.socks.nec.com/.
See also Question 6.
9. Does SOCKS handle UDP?
Yes and no. Socks5 protocol includes support of UDP but Socks4
does not deal with UDP.
The Socks5 package from NEC includes a SOCKSified archie client
program which is an UDP application. The RealAudio Player works
with runsocks (UNIX) and SocksCap (Windows).
10. How does SOCKS interact with DNS?
For Socks4 version 4.2 and earlier, Socks4 clients are required to
be able to resolve IP address of remote hosts no matter whether
they are local hosts or internet hosts. Therefore, DNS must be
configured in such a way that SOCKS clients' resolver is able to do
so. Special arrangements are required when more than one DNS
servers is used.
For the extended Socks4 version 4.3, Socks4 clients will be able
to pass on the unresolvable addresses to the Socks4 servers for
resolution.
For Socks5, the clients can also pass the unresolvable host names
to Socks5 servers and the servers for resolution. If one of the
resolvers used by either the Socks5 client or Socks5 servers is
able to resolve a given host, SOCKS will work.
11. What is a single-homed and multi-homed firewall?
Multi-homed firewall has multiple network interfaces and does not
forward packets. Single-homed firewalls have one network interface
card. Single-homed firewall can be used in conjunction with a choke
router that filters packets not coming from the firewall.
12. Is there an RFC for SOCKS?
There is no official RFC for Version 4 of the protocol. There are
two documents describing Version 4: Socks4's protocol and extension
to Socks4's protocol.
There are three official RFCs for Socks5 related protocols.
o RFC1928 describes SOCKS Version 5 protocol, also known as
Authenticated Firewall Traversal (AFT).
o RFC1929 describes Username/Password authentication for SOCKS V5.
o RFC1961 describes GSSAPI authentication for SOCKS V5.
13. What does SOCKS stand for?
SOCK-et-S; it was one of those "development names" that never
left.
14. Why does the password echo when I run rftp?
The password only echoes for anonymous ftp. This is considered a
feature.
15. How do you traverse multiple firewalls (socksified
SOCKS server?)
There is a socksified Socks4 server, rsockd. It is included in the
Socks4.3 beta release. See README in the release.
The Socks5 package from NEC comes with the support of multiple
SOCKS server traverse. Details can be found at
http://www.socks.nec.com/.
16. Why do I see "inetd[]: socks/tcp server failing
(looping)" in my logs?
This message displayes when the socks server running from inetd
receives too many connection requests. Run the socks server as a
standalone daemon to solve this problem.
Contributors:
* rk@Unify.Com - Ron Kuris, Unify Corporation
* steve@syl.dl.nec.com - Steven Lass, NEC USA
* wlu@syl.dl.nec.com - Wei Lu, NEC USA
Vova
