🚀 go-pugleaf

gmcnair@gil.com.au wrote:
: We have a Linux server connected to a service provider using a 
: dial-in PPP where we get allocated a dynamic IP address.
: This Linux system is connected to a number of Unix and Windows 
: PCs on a LAN using 192.0.0.0 as a domain.

: What we would like to do is to run Netscape locally and route 
: through the Linux server to the Internet via the PPP connection. 

: Is this possible?? 

Yes - this is eminently possible using IP Masquerade. This is exactly
how I give my home ethernet connectivity.

: What do we have to do to achieve this??

1) You will be best off by moving to Linux kernel 2.0.x (if you are not
already there).

2) Get hold of the IP-Mqasquerade mini-howto from

http://sunsite.unc.edu/mdw/HOWTO/mini/IP-Masquerade

This contains excellent directions to help you configure your Linux box.

3) Once you are up and working, tell your local ethernet PCs that your
Linux box is the gateway (or router) and away you go. Note - ping and
related utilities (traceroute) do *not* work from masqueraded clients!

Depending on the usage your local PCs wish to make of the link, it could
well assist in saving bandwith if you...

a) Set your Linux box up as a local (secondary, caching only) name
server for the local clients. Further bandwidth saving can be achieved
by then declaring your ISPs nameserver as a 'forwarder' - thus any
queries are actually handled by the ISP's DNS and only the answer is
passed back (rather than your nameserver handling the whole query if the
answer is not in its cache).

b) Set up a caching, proxy web server on your linux box. This will
ensure that web access is as efficinet as possible (investigation of
squid is recommended here, particularly if your ISP runs squid).

c) You may want to set up a local anonymous ftp server on your Linux
box. This will allow your users to get and share files without incurring
repeated download of the same file.

As a final word of advice, I would suggest that you buy the O'Reilly
"Building Internet Firewalls" book. You need to consider the security of
your Linux box and its attached LAN if you are doing this. Your LAN is
safe behind the masquerade (and with dynamic IP allocation, it is even
more safe) *provided* the security of your Linux box is not compromised.
You should think through the implications of security of your Linux box
and quite possibly use the firewalling features of ipfwadm as well as
its masquerading features.

Please feel free to email on this issue for more discussion if you wish it.

--

Robert Hart                                  hartr@hedland.edu.au
Voice: +61 (0)91 72 0429                     Fax:   +61 (0)91 72 3560
Hedland College, PMB 1, South Hedland WA 6722 Australia