Reflector

[Geoff Shang]

Hi:

I've not actually done it, but this should work.  Using ipmasqadm, here's
an example of forwarding the UDP packets:

ipmasqadm portfw -a -P udp -L `ipofif ppp0` 2074 -R <internalhost> 2074

OK, the _l and -R specify the local and remote details.  the `ipofif ppp0`
is actually a call to a script that gives the ip of the ppp0 interface.
This is a script that comes with the debian ipmasq stuff, but it's just a
standard shell script so you can use it if you want.  The problem for
dialup users is determining their dynamic IP, and this gets around this
problem quite nicely.  <internalhost> is the machine where you want the
packets to forward to.  The 2074 in both cases are port numbers and, of
course, they don't have to be the same if that suits your application.

I've also used uredir on someone else's system, but can't vouch for it
except that it appeared to work.

Now there's a bit of argument about what you need to forward.  I found
that 2074 and 4074 were sufficient to forward.  Others say to forward 2075
and 4075 as well as 2076 and 4076 as well.  I think the 76 ones are TCP
anyway, and I found performance worse with the 75 ports forwarded, so
experiment and see what works best for you.

Geoff.