Chile Forum

admin wrote:is it one of those new VTR wireless Motorola modems?

If it's the Motorola SBG900, it has a firewall. It's configurable by connecting to the single LAN port, opening a browser to 192.168.100.1. The factory default for username and password is "admin" and "motorola". Once you get in there are options for the firewall.

I have a link to the manual if he needs it (if it really is this model. I'm thinking it is because it's what they installed at my wife's family's house.).

Mark

muntaman wrote:Looks like a case of VTR "protecting" their customers by giving us modems we can't alter.

I've never connected a router to a router. It sounds like it should work.

You could try a few things:

1. Go to www [dot] grc [dot] com/default.htm and scroll down to the "Shields Up" link. (Also www [dot] pcflank [dot] com/scanner1.htm). This will scan your public IP address and tell you what the world can see.

2. If VTR is advertising that they are selling you the SBG900, you could call them and demand what you thought you paid for. You could argue that you have the product manual, and what you received is false advertising. If you have the results of firewall tests showing there is no firewall, that would be even better.

2a. You could ask if they have a cable modem-only device. As to exchange for it, then buy a Linksys WRT54GL and reflash it with DD-WRT (open source firmware giving a lot more options). That might be worth the price of buying something (when buying a new cable-modem wouldn't).

3. On the back of the modem there is a pin hole to reset it to its factory defaults. (Hold it down, power on, continue to hold it for 30 seconds). Before doing this, write down all the values. Maybe resetting it would cause the router options to reappear.

4. If you Google for "SBG900 firmware download" you'll find some sites offering it. nodevice [dot] com seems to have a good reputation. The cell phone enthusiasts refer to it a lot. But, since Motorola doesn't seem to offer this firmware itself, you don't know where this copy came from. You might "brick" your modem. That wouldn't be too bad. Call VTR and make them fix it (they broke it). But, there's also a risk someone could hack the firmware and have it forward IP traffic elsewhere. (Personally, I wouldn't do this. I only mention it because you might find it yourself.).

5. "Bricking" the modem might be a good idea if VTR is obligated to fix/replace it. If you could get a tech to the house, maybe you could learn more about the options available to you.

Mark

MarkF wrote:I've never connected a router to a router. It sounds like it should work.

BTW: I was searching around about cable modems because this discussion got me to thinking about bringing a modem on my next trip. I found this discussion: forums [dot] speedguide [dot] net/showthread.php?t=77465 . This guy's trying to connect a Cable modem/router (CR) to a cable modem. Not exactly the same as what you're trying to do (router to router). But, it might give you some ideas of what to try (clone MAC addr, hardcode VTR's DNS addresses in the PC's TCP/IP properties, etc.).

You mentioned the possibility of buying a cable modem. Do you think VTR is obliged to allow the use of any modem? Usually you have to call the cable company and provide the MAC addr of the modem. They hardcode it into their system to allow access. Are they required to recognize any MAC addr that didn't come from them?

Also, it sounds like inaccessible firmware is common. I looked at two Linksys modems. No firmware. I searched for how to configure these models. Found a thread about someone fighting with Comcast (a US cable service) to get them to upgrade his Linksys modem (one he bought, and they claimed they didn't support). It was a Catch-22. They let him buy his own modem and connect it to their network. Linksys only lets cable companies upgrade firmware (remotely). And, the cable company claimed they couldn't because it wasn't one of their supported modems. (However, two days later his modem was upgraded). That story makes me nervous about spending $70 US for a modem to bring to Chile.

Mark

muntaman wrote:I'm using a bittorrent client and it works perfectly so even if the firewall was enabled and visible in the admin console, all of the ports must be open by default.

I've been thinking about this more. How insecure is it to open all the ports on a router? The router has to use Net Address Translation (NAT) because it's maintaining one public IP address, and managing a mapping of overloaded requests to potentially multiple private IP addresses. I know for outbound requests, it maintains a translation table so the incoming response packets can be mapped back to the internal IP that sent the request. But, how would unsolicited packets work? If all the ports are open, doesn't that mean the router itself is vulnerable, but nothing can go further? How would the router know where to route those packets that it's not expecting?

I don't understand how that works. There must be something wrong with having all ports open because we hear so much about it. But, I don't see how computers behind a router would be affected.

BTW: I found out last night my wife's family's modem/router is dumbed down like yours. I asked them to call and find out if the company only does this to protect against nuisance support calls (firewalls can be complicated), and if they will restore full product functionality on request. I also asked them to find out if there are any restrictions on purchasing cable modems from any vendor.

Mark

muntaman wrote:If your LAN device is assigned a WAN address, then there's no NAT translation occurring. It's like putting a device on the public network.

After further thought, I think I'm wrong. The SBG900 has an option to specify the LAN's IP address, and starting address (for generating internal IP addresses). The cable company may have configured this to serve addresses within its public IP block. I.e., everyone with this modem/router may be getting the same IP address(es) you get.

The only way to know for sure would be to enable a server (http?) on your computer and see if it can be reached from another computer not on your LAN. I don't think a simple ping would work because, if they're serving public IP addresses to a private network, there's a possibility the address really exists publicly. You wouldn't know if you're reaching your machine or a computer legitimately using that public address.

Mark

muntaman wrote:I would be interested to hear what response you wife's family get (as I don't speak much spanish and hope that they do).

They said they called and VTR said they won't restore the modem's firmware, and they don't allow privately purchased modems to be connected to their network.

But, as I said, her family isn't aggressive about these issues. They sigh every time I ask them to check into something like this. If you learn something different, please provide an update.

Mark

you want to start by using nmap to see what ports are open, and what they are serving.

Personally, I simply would not allow them to install one of those. We are about to dump VTR I believe, even though it means giving up one of our long time buisness phone numbers. They are just too Micky mouse an operation to do buisness with.

admin wrote:Personally, I simply would not allow them to install one of those. We are about to dump VTR

Does that you were successful at purchasing your own cable modem and getting VTR to allow it to be used?

My wife's family was told they don't allow that. But, it wouldn't surprise me if they didn't try hard. If anyone's been successful at using their own cable modem, I'll buy one and take it with me. Try to press the issue while I'm there.

Mark

We have the modem they use for phone service, it has port for internet. Beyond that is our network. If you are getting phone service from them also, you do not need that wireless modem thing they are installing. Put your own wireless router after that.

My network is my network, and I really do not want VTR in the middle of it.

admin wrote:We have the modem they use for phone service, it has port for internet.

Thanks. That sounds different. Just an ordinary modem, or modem with a VOIP ATA built in. They have a modem with a router built in. Usually the combo units (like a router with a wireless access point built in) are good deals because they're cheaper than buying the individual components. But, I'm realizing this is a bad idea for cable Internet because you can't update the bios (even for the non-modem components). It's entirely controlled by the cable company.

Maybe the next thing to do is ask my wife's family to ask VTR if they can "rent" just a modem. Then plug a router into it. They won't like that idea because they've been thinking they're getting this SBG900 "for free" at the end of the contract. But, in the long run it would be better to consider it wasted money, particularly the way VTR removed features.

Mark

I am sure they will get it for free. It will make a nice bookend. It is all a scam. What do you with a modem that has been flashed with proprietary settings for one ISP. By the time the contract is up, even VTR's system will not use them.