Re: Need help to connect to ISP!

Todd Fries (tfries@umr.edu)
Sun, 4 Feb 1996 14:29:17 -0600 (CST)


> If you have only one IP address, then you have only one machine to send
> packets to. Ah, you say, but my machines all have different addressses,
> 192.x.x.x. But this is where the problem is 192 is an address that can't
> send packets outside. Anyone can construct a 192.x network (including
> one with exactly the same addresses as you) and connect it safely to the
> internet anywhere, but only because no gateway/router/brouter on the
> internet will (should :-) ever transfer 192 packets, so those machines
> can never communicate outside their network.

What RFC states the use of this address? I thought that 192.168.x.x and
110.10.x.x were the 2 reserved networks. I didn't realize that 192.x.x.x
was open for use...I thought I've connected to 192.x.x.x address over
internet? Maybe I'm wrong..

> SOCKS firewall:- This is fine as long as you have every program you want
> to run SOCKS aware (replace libraries and they should all work except for
> any which have been statically compiled etc..). But you still don't count
> as properly connected. For example, running an FTP server on your PC
> won't work properly.

Ah, I now understand the limitations of SOCKS.

> Now here's where you could be really clever. Build a connection system
> (into the gateway code of linux) which remaps internet connections from
> the PC on it's ftp port to a different port on your linux machine. Then,
> it will seem as if your Linux machine has two ftp servers running, and you
> can connect to the second one with
>
> ftp your.machine.name 3435

This is called 'bouncing' incoming connections to pre-selected ports on
an internal network..I personally know someone who has written a program
for this purpose, but he refuses to allow just anyone to use it, and
furthermore, he absolutely denies me access to the source...

What I believe one could use is ip_masquerading. It at least gives the
machines on the local network access to internet.

> Alternatively, you could change service provider.

> Serious service providers provide static addresses. The address is meant
> to identify the machine. Just because it's cheaper dosen't mean it's
> better.

Some of us don't want to pay for primetime services. Many would rather get an
ip on internet whenever we dialup for a fixed rate. Others, like me,
have no choice in the matter, as dialups provided by the University don't
provide fixed ip's, rather dynamic ones, one per modem.

-- 
Todd Fries...tfries@umr.edu
http://www.cs.umr.edu/~tfries