On Sat, 09 Feb 2008 22:29:15 -0600 [EMAIL PROTECTED] wrote: > Sorry for the OT, but unable to raise anyone at comcast right now. Really? I didn't think that was possible... although sometimes it's good to call twice, get another opinion.
> I think I recall having read somewhere that one can do something to > discover what devices are on a network (Home lan). And what there > addresses are. the network devices of those boxes have fc1918 private addresses i'm sure. even if your router would forward packets from the outside in (which can usually be configured), comcast isn't going to route them to your router. your external address is, of course, somewhat available, and the device listening to that address (your router) is therefore potentially vulnerable. Run a good firewall and you'll have knowledge of what happens to incoming connections (generally, it would be best to ignore them). linux makes a very good firewall. > I've recently switched from DSL to Cable connection but still have > both working currently. smart! > I had assumed my netgear-firewall/router would find the Cable modem > and be able to talk to it, but that isn't happening. i've never heard of that happening. ... > I can connect the cable modem direct to a pc and using the software > that comes with it establish a connection to the internet, but I > wanted to have that firewall/router in between the cable modem and > home pcs. In my experience (w/ comcast), you connect the modem to a network port via ethernet and then request a dhcp address. I never used comcast's software in windows or linux. > But that is only on a windows machine. > The help file that comes with the modem provides no information about > how one talks to the modem. No ethernet address is supplied. However > it is an ethernet device and connects to the pc with ethernet cable. > > Apparently comcast felt it wiser to provide no details and let its > software do the connecting. It's more transparent. The network device on the modem holds your public ip address. The modem has nothing to say. Some modems, no doubt, have built-in gateway/router/firewalls, but not all. > But can't I learn the IP address (inward facing) of the modem? The IP > from outside is of course visible to ipconfig, when connecting to > internet from a windows machine thru the cable modem, but I see > nothing that indicates what its lanside ethernet address is. It doesn't have one. (If it did, you'd need to use it to reach the outside.) Instead your outside ip is 'on' the computer itself. > Its obviously connecting to the pc with dhcp so setting the netgear to > listen for dhcp seemed like it should work... but doesn't. the modem doesn't do the dhcp though, the computer asks and a dhcp server in comcast-land gives out a lease. i would think your router supports it - but you'd be using dhcp to request a lease from netgear's point of view, not listening. 'listening' for dhcp sounds more like serving addresses on the local network than using dhcp for external configuration. > I thought I would be able to connect to the cable modem with a browser > and maybe learn enough to make the netgear router/firewall connect to > it, or one of my gentoo boxes, so have tried a few of the > semi-standard addresses other ethernet hubs/routers etc default to, > like 192.168.0.1, 192.168.1.1 and a few more. as i said, it probably won't have such an address. it is transparent to everyone but comcast itself, which evidently delivers some sort of point-to-point-like service . but the good news is gentoo _should_ be able to use it just fine. i didn't have any problems. the netgear should do fine as well, i'm surprised you're having problems at all. well, i hope that helps. feel free to contact me if you have any more questions. -- gentoo-user@lists.gentoo.org mailing list
