How dumb would it be to reset the modem/router provided my my ISP?

March 27, 2008 5:38 AM

How dumb would it be to reset the modem/router provided my my ISP?

The modem/router in question is a Paradyne 6381-A3.

My ISP is a small town operator, not Comcast, Verizon, etc.

The reason for this is that I want to try and get port forwarding working, and the problem is that I can set it up all I like on my Linksys wireless, but the modem is also functioning as a router and it's not configured as I would like.

I have directly connected to the device, but I can't get the admin interface to come up. I have tried the IP the manufacturer says is the default, as well as a few educated guesses and I can't get anywhere. From the manual, it seems that this device should have a nice little web interface, and it does offer the option to set up a DMZ (which I would like to put the Linksys in), but I just can't get at it.

Now I'm not sure wether my ISP has set up the device to either not respond to http requests for the admin interface (if that's even possible), or if they've put the interface on a different IP from the default (which then leads me to believe that they would have also set the password to something I wouldn't easily guess).

There is a reset button, and what I'm concerned about is wether triggering it is likely to also wiping the credentials it uses to log into the DSL network. When they installed the DSL, the installer literally just plugged it in, attached the phone line and then connected it to the wireless router and it worked. There was no set-up done here.

Can they be controlling access on their end, or is it very likely that it was set up prior to their arrival here and it is very likely that pressing reset is going to wipe the credentials it needs to connect and leave me internet-less?

If I lived closer to their offices, I would press it and try my luck, but they're over 20 miles away, and I doubt that my follies are going to be a high priority for them to rectify.

So, basically, what's the risk of resetting the thing?

posted by jcruden to computers & internet (11 comments total)

If you reset it, it will definitely wipe out the connection settings configured in the device by your ISP (In my experience with similar Westell brand devices).

In your situation, the most preferable setup would be to reconfigure the modem/router into "bridge mode", meaning it will function only as a modem, and set the required ISP settings in your Linksys. This way, it won't NAT at all, and all port forwarding/etc will be done by the Linksys.

The advantage to having a small town operator, is that they are more likely to allow this, and walk you through the change than Comcast or Verizon. Give their tech support a call.
posted by effigy at 6:07 AM on March 27

Most likely, "Yes.", resetting the modem/router will wipe the settings and (therefor) disconnect your DSL. You are correct in guessing that the best course of action is to find access to the web-management page for the modem/router and review/write down all the settings before toying with it. Since you cant find the IP, you may want to try using a tool such as SuperScan to scan your entire internal network range. It will tell you what other IP's it detects (one should be your modem) and it will also tell you what ports are "open" on that device. (so for example, it might detect 192.168.1.256 and on that IP, port 80 HTTP is open, which is a pretty good indication that IP is your modem,etc.)

It WONT however tell you the admin logon or password,.. so you may still be out of luck. (unless your ISP uses some generic pattern such as serial number, or account name,etc)
posted by jmnugent at 6:36 AM on March 27

Check the configuration on your Linksys router. Is it getting its WAN IP address information via DHCP (automatically)? If so, then it should be automatically assigned a gateway.

Assuming that your DSL router provided by the ISP is NATing your public address to a private subnet, the gateway it assigns to your Linksys router should be the IP address of the DSL router.

It is possible that the device they have given is capable of disabling the NAT. I suggest that you contact your ISP and request that they reconfigure this device or give you a device that is not doing NAT. A double NAT (which is what you are describing is your scenario) can cause problems with certain types of network traffic. Especially if you are gaming, it can make it hard to keep a constant connection to a gaming server, etc. This should be reason enough for them to sort you out.
posted by doomtop at 7:01 AM on March 27

Okay, putting both of your responses together I've arrived at the point at which I give up.

Looking at the Linksys router, it is getting connection from DHCP, and I think you're right that the gateway that it's been given is the modem/router. That IP, of the modem/router does respond to a ping, but SuperScanning it turns up nothing fruitful, leading me to believe that they've got it set up in some Machiavellian manner.

A this point, I'm entering diminishing returns territory. I've dealt with the support 'team' on this ISP before, and it's organized in a manner which seems designed to protect the engineers from customers, and the one woman who keeps the key to their gate knows nothing of computers, the internet, and seems completely incompetent. We have noise on the phone line which is coming from the DSL, but isn't entirely curbed by filters, and we've gotten nowhere after numerous attempts to get someone to diagnose our problem, never mind solve it.

We should be moving in a few months, so I'll just put this out of my mind. I had a niggling thought that there could be a chance that the modem could be reset without DSL collapse (as my knowledge of such things is limited), but it seems that collapse would be expected, so I'll give up here.

Thank you both for your help.
posted by jcruden at 7:38 AM on March 27

Don't give up!

This shouldn't be real hard. Type ipconfig in your command prompt. The numbers listed for default gateway is ip address for the router. The management page is usually accessible by typing that IP in your address bar of your browser. But sometimes ISPs will disable that and only allow telnet. If that's the case, in your command promprt type "telnet 192.168.1.1" (or whatever your address is). You will still need the password to access that. Try "admin" or "password".

If that still doesn't work, call your ISP and explain that you would like to use your own router. Most modem/routers can be set to bridge mode. If there is no specific mode, simply turn off NAT and DHCP, and assign your new router a static IP.

If you need more help, send me an email.
posted by cp7 at 8:10 AM on March 27

Can they be controlling access on their end, or is it very likely that it was set up prior to their arrival here and it is very likely that pressing reset is going to wipe the credentials it needs to connect and leave me internet-less?

Probably. They might be using PPPOE and the reset will wipe the user account. The best thing to do is to call them and tell them you want access to the admin interface. I cant imagine them denying you this.
posted by damn dirty ape at 9:01 AM on March 27

You seem to think there's some conspiracy theory going on here, but I think the real problem is that you are double-NATing, which means that the network your wireless device (laptop?) is on is different than the network your ISP router is on, making it impossible for you to access the ISP router from your laptop. This is how you've got it:

ISP Modem plugs into the wall, provides network access. Since it is also a router, it uses a protocol called DHCP to hand out IP addresses to all the computers connected directly to the router. For arguments sake, let's say it hands out IP addresses in the range 10.0.0.x, with the ISP router being 10.0.0.1.

You bought a Linksys wireless router for your wireless laptop, and thinking you were doing the right thing, used an ethernet cable to connect one of the LAN ports of the ISP router to the WAN port of the Linksys. The problem with this is that the Linksys is also a router, and so it gets assigned an IP address of 10.0.0.x (say, 10.0.0.2) and then uses DHCP to hand out it's own IP addresses, lets say in the range (192.168.1.x, with the Linksys as 192.168.1.1). Your laptop then connects and gets an IP address from your Linksys, which will obviously be in the 192.168.1.x range (say, 192.168.1.2).

Here's where we encounter the problem! Your laptop now has an address of 192.168.1.2 and you open your browser and try and go to 10.0.0.1 (to access the ISP router). Problem is, the linksys is configured to only recognise addresses in the 192.168.1.x range, so it doesn't know what to do with the 10.0.0.1 address you've given it. Furthermore, the Linksys knows that 10.0.0.1 is a private address, so it won't pass it through to the ISP router through the WAN interface either, meaning your browser gets confused and bingo, conspiracy theory!


SO, how do you solve this problem? Well, after ALL that explanation, the solution is actually really easy. Just grab the cable that runs into WAN port on the Linksys and plug it into one of the LAN ports on the Linksys instead (I assume it has LAN ports?). This effectively connects the Linksys as a simple switch/wireless access point and means that all your computers (wireless and wired) end up on the same network. You might also need to log into the Linksys and disable DHCP, otherwise occasionally computers on the network will get 192.168.1.x addresses (in my example) and since the WAN port on the Linksys isn't connected, this will mean they don't actually get internet access!

One more thing... You don't say what OS you are using, but assuming you are using WinXP, you can go out to a command prompt and use ipconfig to check your IP address at anytime (as cp7 suggests). This should allow you to check what I'm saying by using ipconfig to check your IP, making the changes I suggest, switching everything off and back on, and then trying ipconfig again.. If I'm right, then your IP should change noticeably (not necessarily between the examples I give, but something similar).

Let us know how you go, and feel free to mefimail if you need more help.
posted by ranglin at 4:30 PM on March 27

Oh, I forgot to mention! Once you fix the double-NAT issue, then you should be able to get into the admin interface for the ISP router, which is what you wanted originally.. :)

(PS. Another option, of course, if you JUST want access to the admin interface of the ISP router is to use an ethernet cable to connect your laptop directly to the router... It will then get a 10.0.0.x IP address and you should be good to go... Note however that you'll still have problems with port forwarding, as you'd then have to setup port forwarding on both the ISP router and the Linksys, and I'm not sure how well it would work).
posted by ranglin at 4:33 PM on March 27

ranglin: I don't think Linksys routers are going to identify private address space and drop those packets. In the scenario you describe, the Linksys would pass the request for 10.0.0.1 to its default gateway (the DSL router) when it doesn't recognize it as being part of the LAN.

The double NAT shouldn't prevent the OP from accessing the DSL router at all.

jcruden: I suggest that you don't connect the DSL router LAN to the LAN on your Linksys. This is only going to cause confusion and will not help you with forwarding ports without access to the DSL router's interface. It will also make it harder for your ISP to assist you in getting to where you want to be.

I think the best thing you can do, aside from not worry about it until you move, is to contact your ISP and let them know specifically that you want their equipment NOT to perform NAT. If they turn that off, you're in business. If they won't/can't, then you need access to the DSL router interface for configuration of port forwarding, otherwise you may be stuck.
posted by doomtop at 6:39 AM on March 28

doomtop: How will connecting the Linksys LAN to the ISP router LAN cause confusion? It will remove the double-NAT issue (which he should do anyway), and may also allow him to access the ISP router to change the port forwarding settings (I've been here before and have had problems with the two network issue in the past, despite the common gateway.

Frankly, I think it's better than your solution, which is basically to shrug your shoulders and say "Oh well". As you say, many ISP's won't turn on bridging mode (or simply can't with their hardware choice), and so it seems to make sense to turn the Linksys into a glorified wireless access point, doesn't it? Or do you think that double-NATing is a sensible thing to do?
posted by ranglin at 1:11 AM on March 29

While it would "work" it is not the "correct" thing to do. When I say it will cause confusion, I mean on the part of the ISP becoming confused by the unorthodox configuration and therefore making it more difficult for the OP to get support from his ISP.
posted by doomtop at 2:08 PM on April 2