On Fri, 05 Mar 2004 22:07, Christopher Sawtell wrote:
> On Fri, 05 Mar 2004 21:31, Volker Kuhlmann wrote:
> > > The fact that the device can act as a DHCP server does not suggest that
> > > it can also do NAT.  The two are not related.
> >
> > I assume we're talking about their cable modem, not their ADSL
> > whatever.
>
> That's my understanding of the matter.
>
> > The modem comes with no useful documentation, and there is no
> > IP for the modem itself available. That means if you want to send any
> > packet to the modem, you're out of luck, it's not addressible.
>
> Oh? How come I can do this? I'm genuinely interested.
>
> [EMAIL PROTECTED] chris $ ping modem
> PING modem (192.168.100.1) 56(84) bytes of data.
> 64 bytes from modem (192.168.100.1): icmp_seq=1 ttl=254 time=7.51 ms
> 64 bytes from modem (192.168.100.1): icmp_seq=2 ttl=254 time=4.84 ms
> 64 bytes from modem (192.168.100.1): icmp_seq=3 ttl=254 time=4.85 ms
> 64 bytes from modem (192.168.100.1): icmp_seq=4 ttl=254 time=4.82 ms
>
> --- modem ping statistics ---
> 4 packets transmitted, 4 received, 0% packet loss, time 3031ms
> rtt min/avg/max/mdev = 4.829/5.509/7.510/1.158 ms
>
> Port 80 on the modem is open too.
> Have a look, it's quite interesting. Same O/S as the one NASA sent to Mars.
>
> > I've heard that the link between modem and Telstra is NATed,
>
> I gather, looking at the log on the modem, that it is a DHCP address
> permanently allocated to the MAC address of the modem as viewed from the
> Telstra side. There is a tftp server, visible from their side, running
> which allows T/C/P to send a particular config setup to your modem. This is
> how they set the traffic shaping etc., etc..
>
> > but who cares, it's transparent.
>
> It is, as wide as the proverbial barn door.
>
> > View the modem as a dumb cable/ethernet bridge.
>
> It's quite a bit brighter than my understanding of meaning of the word
> 'dumb'.
>
> > If it does dhcp, count that as a bonus.
>
> A bonus of, imho, dubious benefit, because there is no IP packet filtering.

what is the connection between dhcp and packet filtering?

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