networking question

[dkff49]

Well, I finally got a chance to start getting this network up and running and run into an unexpected problem. Whenever I add the router in line I lose the internet.

I put the wireless router in line between the dsl modem and the computer just to make sure things are going to work before I stuff the wireless into the ceiling and I lose all internet access. As soon as I take the router back out though the internet comes back. We also tried to connecting a laptop directly to the modem and again no internet. It seems that the only way to the internet works is to have the regular desktop computer connected to the modem and nothing else.

I know there is nothing wrong with the equipment because I took it to my house and connected it the way it will be connected here and it worked with very little effort, but as soon as I try to put the router in between the computer and the modem things go bad.


Is there a way that the modem may be somehow blocking all access to the internet other than the original computer? I find this a little odd since at some point this organization will probably want to replace the computer, but I can't figure out any other reason why the system would be acting this way.

All suggestions are welcome.

[bbosen]

When you insert the new router between the modem and the computer, it's going to create a new "IP Subnet", using a different range of IP addresses. Perhaps the computer(s) you are using are not adapting to the new subnet in the expected way? If the computers you are using to test Internet access are using the well-known "DHCP" (Dynamic Host Configuration Protocol) system, then they should automatically netotiate a new IP address from the new IP subnet after a re-boot. Did you try rebooting those PCs?

If those PCs have a "static" IP address, then they won't even try to use the new subnet.

Perhaps that is your problem.

You can learn all of the fundamentals of DHCP and Static IP addresses by watching the 2 free movies that are available here:

http://www.askmisterwizard.com/Netw/InternetAddresses/InternetAddresses.htm



Regards,



Peabody

[bbosen]

I thought of another possibility: "Ethernet Addressing". Some ISPs tie their DSL Modems directly to the Ethernet address of the single computer that is first used with them. It's possible (though not commonplace and not very nice) to restrict IP address to JUST that Ethernet address. Some ISPs have been known to do that, but it's controversial, and, understandably, users HATE it. If that's what is happening, you can probably tell your new wireless router to "emulate" the Ethernet address of the laptop that has been working all along. It will then deceive the ISP into thinking that that laptop is still connected.


Regards,



-Peabody-

[Vulcan]

I thought of another possibility: "Ethernet Addressing". Some ISPs tie their DSL Modems directly to the Ethernet address of the single computer that is first used with them. It's possible (though not commonplace and not very nice) to restrict IP address to JUST that Ethernet address. Some ISPs have been known to do that, but it's controversial, and, understandably, users HATE it. If that's what is happening, you can probably tell your new wireless router to "emulate" the Ethernet address of the laptop that has been working all along. It will then deceive the ISP into thinking that that laptop is still connected.


Regards,
-Peabody-

Not in this case.

[dkff49]

I have tried restarting the computer and it did not resolve the problem.

I have even tried putting a new computer directly inline with the modem and attempted to access the internet through the wireless with the new computer and both times no internet.


Vulcan why would that not be the case. I was starting to wonder if there was some kind of address filtering as well.

[RTHolmes]

How do you find the mac address on a computer? This way I can pass this knowledge on to my co-workers so that they will be able to access the network using their computer, which is the main purpose of the wireless anyway.

if you use MAC address filtering, you will have to edit the router config every time a new network adapter needs to join the network, as well as telling the user the pre-shared key (PSK) for WPA. considering its trivial to spoof MAC and its a pain in the arse to administer, I wouldnt bother with MAC filtering

[gyrene81]

I have tried restarting the computer and it did not resolve the problem.

I have even tried putting a new computer directly inline with the modem and attempted to access the internet through the wireless with the new computer and both times no internet.


Vulcan why would that not be the case. I was starting to wonder if there was some kind of address filtering as well.

When you put that new router in, you have to power cycle the modem before the modem is capable of picking up the info it needs from your ISP.

You might have to change some things on your network to do this. First thing is to get that new router configured so it's not pushing I.P. addresses. Whatever system you're gonna configure it from, make sure that computer is using DHCP instead of static IP. You can configure the router "offline" by powering it up without being attached to the modem and connecting to it with a computer via network cable. Open the "admin interface" setup the parameters you want, then attach it to the network.

As Holmes says, DO NOT USE MAC FILTERING...it's a useless pain in the booty effort.

[dkff49]

Thanks for your responses guys. I knew I would get help here.

I did power cycle the modem but that also did not help.

Where do I look to make sure the computer is on DHCP? As a side note we were also trying to use a laptop which connects with other networks with no trouble accessing the internet, so I am sure it is set up for DHCP. I have been into the admin of the router and it is setup for DHCP also.

The MAC filtering has not been started yet since I am just testing the system before I put the router out at it's permanent location. Unfortunately the person they have as administrator for the computer security wants the MAC filtering on when the system goes operational. That decision is really out of my hands, but again it won't used until the router goes to it's permanent location.

[gyrene81]

Where do I look to make sure the computer is on DHCP? As a side note we were also trying to use a laptop which connects with other networks with no trouble accessing the internet, so I am sure it is set up for DHCP. I have been into the admin of the router and it is setup for DHCP also.

There's the problem...it's over riding the other router by issuing IP addresses in DHCP mode. Just set it up as a "gateway" with no other functions other than to allow wireless access and let the other router issue IP addresses.

The MAC filtering has not been started yet since I am just testing the system before I put the router out at it's permanent location. Unfortunately the person they have as administrator for the computer security wants the MAC filtering on when the system goes operational. That decision is really out of my hands, but again it won't used until the router goes to it's permanent location.

Just have the "administrator" read this stuff (common knowledge):

http://blogs.zdnet.com/Ou/index.php?p=43

http://www.lockergnome.com/it/2005/01/18/the-pitfalls-of-mac-filtering-2/

http://www.maxi-pedia.com/how+to+break+MAC+filtering


As long as you use WPA or WPA2 security...maybe even hide the SSID...you have few worries.

[dkff49]

There's the problem...it's over riding the other router by issuing IP addresses in DHCP mode. Just set it up as a "gateway" with no other functions other than to allow wireless access and let the other router issue IP addresses.

I may have confused you. At this point in time we have only been trying to use one router, because of the loss of internet whenever we insert a router in between the computer and the modem.

the test we performed was
computer 1 (hardwired) and computer 2 (wireless connection)
 connected to wireless router
    connected to modem

with this we have no internet

when we put the original computer back onto modem with no router we have internet
when we put computer 2 only on modem with no router we have no internet

[Vulcan]

Vulcan why would that not be the case. I was starting to wonder if there was some kind of address filtering as well.

Because the modem would present it's mac address.

[dkff49]

Because the modem would present it's mac address.

When and where would that be?

[Denholm]

...when we put the original computer back onto modem with no router we have internet
when we put computer 2 only on modem with no router we have no internet

Did you try connecting computer 2 via a cable?

[dkff49]

Did you try connecting computer 2 via a cable?

Yes i did a couple of weeks ago when i originally tried it. This past weekend was actually the second attempt at trying to get anything out of this system. Of course I take the routers home and have no real trouble getting it to work but getting things to operate at work and the problems start.

Additionally i also connected the wired only router with both computers and still no internet as long as there is a router between the computers and modem.

[Denholm]

Have you tried disabling NAT on the router so it acts as an access point (Make sure you jot down any information given just after disabling NAT)?