AFAIK the cablemodem is a transparent ethernet bridge.  Internally on their
side Paradise/TC can talk to the modem on an ip about 172.x.x.x.

As for pinging 192.168.100.1, then your cablemodem must be a newer one.
Mine are the older GE and the older motorola ones, and don't respond on that
IP  (last year we would have had a workstation on that IP.)

The cablemodem cannot do NAT, but it does have the possibility of routing up
to 16 or 32 real IPs, provided your ISP will sell them to you.  Thus you can
have 202.0.37.2 and .3, and the cablemodem will route each IP to an internal
machine.   But P/TC don't do that... Maybe when IPv6 is out....


-----Original Message-----
From: Volker Kuhlmann [mailto:[EMAIL PROTECTED] 
Sent: Saturday, 6 March 2004 1:25 p.m.
To: [EMAIL PROTECTED]
Subject: Re: Telstra cable


> [EMAIL PROTECTED] chris $ ping modem
> PING modem (192.168.100.1) 56(84) bytes of data.

Cool, didn't know that. Works for me too. Funny thing is, the firewall has

Destination     Gateway         Genmask         
0.0.0.0         203.79.122.1    0.0.0.0         

and therefore theoretically, the packets to 192.168.100.1 should go to
Telstra's gateway. I conclude the modem is intercepting them although they
aren't addressed to it, and that's the only reason one can talk with the
modem. The modem still does not have an addressable interface, there's no
MAC address or arp listing for it. The arp table contains a MAC address for
Telstra's gateway, but not for the modem.

> Port 80 on the modem is open too.

Not much else than 80 though. As one would expect.

> Have a look, it's quite interesting.

Indeed!

> Same O/S as the one NASA sent to Mars.

Yeah, and which stopped working a day after...  hmm. Ok. Never mind.

VxWorks is the most common real-time OS for embedded systems. The company,
Wind River Systems, is rather caustic towards Linux (perhaps because they
don't get royalties? hihiii). 

> > View the modem as a dumb cable/ethernet bridge.
> It's quite a bit brighter than my understanding of meaning of the word 
> 'dumb'.

"dumb cable/ethernet bridge" is a technical term for one of exactly those
modems, I understand. "dumb terminals" are also a lot brighter than what
you're suggesting. (especially when you turn the lights off :) )

> A bonus of, imho, dubious benefit, because there is no IP packet 
> filtering.

Ack. Does seem to exist though:  "Enable DHCP Server  The SURFboard cable
modem can be used as a gateway to the Internet by a maximum of 32 users on a
Local Area Network (LAN). When the Cable Modem is disconnected from the
Internet, users on the LAN can be dynamically assigned IP Addresses by the
Cable Modem DHCP Server. ..."

Volker

-- 
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