faq

穿越防火墙技术代码

Q: I'm not real sure what httptunnel can be used for exactly?

A: It's a generic tool for sending data in and out through an HTTP proxy.
   This is not very useful in itself, so you must run another program
   which uses this data "tunnel".  For example, you could use telnet
   to log in on a computer ouside the proxy.

Q: httptunnel craches my SuSE 5.3 box, why?

A: I don't know, but upgrading to 6.0 seems to help.

Q: I'm responsible for network security in our company.  My question
   is: are there any characteristics of the communication that may be
   detected at the proxy?

A: Maybe.  I make no guarantees.  Use the source.

Q: I wrote 'hts -d /dev/ptyq1' but 'cat </dev/ptyq1' returns an error.

A: Use 'cat </dev/ttyq1' instead.

Q: My friend runs hts at port 8888, but when I try to connect to it,
   there is no response.

A: As for now, hts can't handle multiple tunnels.  You must run your
   own instance of hts listening to another port.

Q: Is there a Windows/95/98/NT version?

A: It's possible to build and run httptunnel in the Cygwin environment.
   See http://sourceware.cygnus.com/cygwin/.

Q: Are there binaries of httptunnel for win32(Windows/95/98/NT) anywhere?

A: On the homepage, there is a link to someone maintaining
   win32 binaries.

Q: Is there a Macintoch version?

A: Not that I know of.

Q: My firewall requires HTTP user authentication (which is currently
   not supported by httptunnel). Do you plan to add something like
   that?

A: Yes.

Q: How hard would it be to implement "hts" as a cgi running on a
   normal web server?

A: hts can't be called directly from the HTTP server, because hts will
   service many connections during the lifetime of the tunnel.  If the
   HTTP server executed a new instance of hts every time a new request
   was made, each new hts wouldn't have access to the prior state of
   the tunnel.

   However, a CGI proxy which forwards the requests to a normal hts
   listening to a port != 80 whould most probably be quite trivial to
   implement.

Q: Have you thought of using HTTPS?

A: It has been suggested, but I'd rather avoid all the nasty export
   restrictions.  You can use external software to get an encrypted
   tunnel.

Q: On REMOTE (brugd.ctrl-c.liu.se) I do the following:
   hts -F localhost:23 8888

   This worked the first time, but never since... now I only get:
   hts: couldn't create tunnel

A: The first hts is still running in the background.

Q: On LOCAL (dhcp-XXX.enea.se) I do:
   htc -F 2323 -P http://internwebb/proxy2.pac:8000 brugd.ctrl-c.liu.se:8888

   Now, I try:
   [root@localhost httptunnel-1.101]# telnet localhost 2323
   Trying 127.0.0.1...
   telnet: Unable to connect to remote host: Connection refused

A: [Christian Brideau] http://internwebb/proxy2.pac:8000 is not
   exactly the proxy's adress.  This is the location of the
   Proxy-Auto-Configure (PAC) file.  This file contains the adress of
   the proxy server.  To discover the real adress, just go to an
   external web page using a browser and then use netstat to figure
   out what adress your browser is using.

Q: Why does 'configure' fail on HP-UX?

A: Because you haven't installed gcc.  If
	CFLAGS=-O ./configure
   doesn't work, you must get gcc, or at least an ANSI C compiler.