odd ip address behavior with cable modem

[bigalt]

Every since my cable company switched, and i got a new cable modem service, I've been unable to connect to any computers in my apartment from outside. Tonight i finally got around to fiddling, and one odd thing i saw is that the ip address my router is automagically getting from our cable service is much different than the ip address I get on the ip-checking websites.

The the router has listed is 10.50.0.xx which doesn't look like a real ip address to me, but it did manage to find a 10.50.0.1 gateway.

Does this mean that the cable company is running some kind of firewall also? I'm picturing some company who bought a T1 connection and has a bunch of 4 port linksys routers daisy chained together for each of our internet connections.

Any way to further test/diagnose what's up (so I can better guide the support people on the phone)?

 

[dc5]

that looks like a private ip to me. (class A)

 

[VirtualLarry]

I've heard of some cable providers using private IP addresses internal to their network for their subscribers, I assume that they run NAT at their actual "upstream" internet gateway, since it's not really "legal" to route to/from private IP addresses. Are you sure that you don't just have to enable some sort of port-mapping or DMZ mode on your router?

For example, my Verizon DSL, the Westell 2200 modem connects using ATM over the POTS line to the line card in Verizon's CO. Now, to the DSL modem, it gets a 10.x.x.x non-routable address and a similar one for the gateway. Both of those, are not to the internet, but to Verizon's internal network. In order for me, the subscriber, to get a "real" publically-routable IP, I have to login using PPPoE over that internal 10.x.x.x link, and then I get a valid dynamic IP from their servers.

Do you possibly need to run PPPoE or otherwise login to get a valid IP? Can you connect outward to other sites? What does a "traceroute" ("tracert.exe" on Windows) show? Mine shows a first hop of 192.168.x.x, which is my local NAT router, then 10.x.x.x, which is the DSL modem/CO linecard, and then "normal" public IPs from thereon out.

 

[bigalt]

Originally posted by: dc5
that looks like a private ip to me. (class A)

though I know how to forward my ports so I can ssh into my machine, I'm enough of a newbie to not understand what you just said

That means that's an ip only visible to those within phonoscope (my cable company)'s service?

Does that mean I have to call to get them to demilitarize or forward ports and whatnot? Would they even by likely to do that?

Originally posted by: VirtualLarry
Do you possibly need to run PPPoE or otherwise login to get a valid IP? Can you connect outward to other sites? What does a "traceroute" ("tracert.exe" on Windows) show? Mine shows a first hop of 192.168.x.x, which is my local NAT router, then 10.x.x.x, which is the DSL modem/CO linecard, and then "normal" public IPs from thereon out.

ahh, looks like you hit the nail right on the head. great, yet another thing I have to learn how to use.

PPPoE, you say. I'll look into it.


edit: dang, I see a really tempting little tab switch on my linksys router that changes IP from "automatic" to PPPoE, but my roommates upstairs are playing FFXI and will probably have temper tantrums if I cut off their connection (again).

Does anyone know if it's a) likely to ask me for a passowrd or b) likely to shut off the internet connection for more than a second if i screw with it?

 

[Xtremist]

That means that's an ip only visible to those within phonoscope (my cable company)'s service?

Correct.

Does that mean I have to call to get them to demilitarize or forward ports and whatnot?

Yes.

Would they even by likely to do that?

No.

In fact, if your router's IP truly is the 10.x one and you're unable to get at least one publically routable IP, there's no way you're going to run any services from home. The reason for this is that if they setup port fowarding for you (say 3389 for RDP), then no one else would be able to use it without changing the default ports. Same goes for any other service, SSH, HTTP, FTP, etc... So the liklihood of them actually doing that for any subscribe is nill. You really need to get at least one public IP...

I thought only some of the wireless companies were pulling this kind of crap. That sucks that you're in the same boat!

 

[bigalt]

it would seem that phonoscope does this by default now, and if you want you can pay 5 extra bucks a month for a vpn account that gives you a public ip.

guess it's time to look into dsl!

 

[VirtualLarry]

That's complete and utter BS, that if you are paying for internet access, that you should get an internet address. It would be like paying for local phone service, but not getting a phone number, so you can call someone, but you have to pay extra to a voicemail service somewhere to be able to recieve calls.

I've never heard of this company. Depending on what country they are located in, I would contact your local trading standards/commerce authority, and check their marketing materials very carefully, to see if they have disclaimers, etc. about not getting an IP address included with their "internet"-access service, and raise holy heck if they are being deceptive about it.