Re: transparent-proxy

Jos Vos (jos@xos.nl)
Sat, 25 May 1996 12:16:04 +0200 (MET DST)

> I understand that CONFIG_IP_TRANSPARENT_PROXY redirects traffic which is
> meant to be sent to a host somewhere on the net to a local socket, so that
> a local programm will receive these traffic. seems very interesting, but
> what can this feature used for ?

To redirect sessions of some protocols (HTTP, FTP, Telnet, whatever you
like) to local proxy servers. This makes it possible to use proxy
servers without having proxy support in clients on your internal network
(that's why it is called TRANSPARENT proxy support).

Some of the more advanced (and expensive ...) firewall packages on the
market also support this feature, mainly because you then don't have to
bother about all kinds of non-proxy-aware client programs.

The proxy servers can be slightly changed "normal" proxy servers
(proxy HTTP servers, servers from the TIS toolkit, etc.) or special
servers.

Another possibility would be to use another server for sessions coming
from internal hosts (e.g., redirect telnet traffic from an internal
host to port 2323, and use port 23 for all other incoming sessions).
This can be easily done via input firewall rules using redirection
(ipfwadm -r ...) using ipfwadm 2.1.

-- 
--    Jos Vos <jos@xos.nl>
--    X/OS Experts in Open Systems BV   |   Phone: +31 20 6938364
--    Amsterdam, The Netherlands        |     Fax: +31 20 6948204