Adding a wireless router to an existing network with Cisco router

When configuring a router as an access point the LAN IP of the router need not be in any predetermined range. It may be anything.

It's a private range, just like 192.168/16.

If the port on the Cisco is a switch/LAN port.

You've confused me a bit. Are you saying that it doesn't matter what I enter as the LAN IP address of the Linksys router?

And then your comment about the port on the Cisco must be a switch/LAN port ... isn't that what all ports are on the back of a router? And if there is a hub, couldn't I just as well plug into the hub instead of directly into the Cisco router?

Michael

Yes. If you are not routing it doesn't matter.

The Cisco is not unlike any other router in that one interface will likely be used for the WAN and another for the LAN.

Yes.

Michael Erb hath wroth:

Sorta. An access point works on the MAC layer (ISO layer 2). It doesn't know anything about IP addresses and such. However, you need an IP address for the Linksys in order to configure it. Select any IP address that is in the same Class C IP block as the Cisco.

10.10.10.xxx or whatever. Make sure the IP isn't already used and that it's not in the DHCP range of your existing Cisco.

If you don't want users on the Cisco to "see" the Linksys, you can literally use any RFC-1918 non-routeable IP address. However, you'll need to manually set the IP address of your managment workstation to be able to access the Linksys.

Ok

It should be a static IP on the Cisco any IP that's not issued by the DHCP server on the Cisco.

On Linksys router it should be the following:

1) DHCP disabled on the Linksys. 2) Configure the Linksys to not obtain an IP from the Cisco, like the router was being a router and it was connected to the modem it would get an DHCP IP from the ISP. You don't want that mode of the router. You want to give or configure the Linksys for the IP(s) its to use. A) IP = a static IP on the Cisco a static IP on the Cisco is any IP that's not in the range of the DHCP server on the Cisco. As an example taking the Linksys router that was being used as a router with its DHCP enabled and it's connected to the modem. DHCP IP(s) start at 192.168.1.100 to the DHCP issue count. If the count is 10, the last DHCP IP that can be issued is 192.168.1.110. Any IP after that is a static IP that's not issued by the DHCP server. B) Subnet Mask is 255.255.255.0 or whatever the Subnet Mask is on the Cisco. C) Gateway IP will be the device IP of the Cisco or whatever that IP that is used to access the Admin screen of the Cisco through a browser.

It should be getting an IP from the DHCP server on the Cisco, as the Cisco is the gateway device.

If set correctly, then you're not going to see any IP that you would see if the Linksys router was connected to the modem and acting as the gateway with it's DHCP enabled. It's going to be an IP from the Cisco just like other machines connected to the Cisco are using its IP(s).

You should be using a LAN port on the Cisco and plug the Linksys into it.

You should also remember that the Cisco may have a 10 user license or something like that possibly, meaning that only 10 IP(s) can be used by users connected to the router including that Linksys using an IP and any machines connected to the Linksys getting an IP from the Cisco. The license will not allow you to use the 11th IP, as an example.

Duane :)

That's LAN port to LAN port on both the Cisco and the Linksys.

Duane :)

Well, sometimes things are so easy it's scary.

So after about a week of worrying about this installation, I proceeded.

First I hooked up a laptop directly to the Linksys so that I could access the WebAdmin panel and turn off DHCP. I also changed the SSID to a more appropriate name. I didn't change the default LAN IP address at all.Then I disconnected the laptop and hooked up the Linksys WRT54G to an open LAN port on the Hub and was immediately able to gain access to the Internet. So that's all good.

However, I can't seem to access the Linksys WebAdmin from a networked computer. If I enter 10.10.10.1, I get the Cicsco router, but if I enter

192.168.1.1 (which is the Router IP of the Linksys) nothing happens.

I'm sure this is a simple thing, but not for me unfortunately. What configuration do I need to change to enable access to the Linksys?

Also, if someone is accessing the Internet wirelessly via the Linksys (the entire reason we installed it in the first place) we want to ensure that they cannot access our local network in any way whatsoever. Nor do we want our ethernet network to show up in their "View Network Connections". Is there some way to set the Linksys up to disallow any other local network connectivity other than allowing Internet access?

I don't know about your Linksys, but some wireless routers can be configured to allow wireless clients access to the Internet (WAN) but not access to the wired LAN. One such is the Hawking HWR54G Rev M (in Advanced Settings I think).

It's called network segmentation. The Cisco router is the gateway router and the Linksys is set back to router mode (hold down the Reset button for

30 seconds on the Linksys to set it back to its factory defaults, which is default of being a router and plug Linksys WAN port to Cisco Uplink ort -- (I think as I have never done it). The Cisco is the gateway for the Linksys, but each will be on their on segments. The Cisco on 10.10.10 and Linksys on 192.168.1 and each serving their own DHCP IP(s) to their machines connected to them and machines on either segment will not see nor can they access each other. I think a machine connected to their respective router will be able to access the router's Admin setup via a browser giving the Device IP of the router.

You may want to call Cisco if you have a current support agreement and ask them for help on what to do and be done with it.

Duane :)

Once again, thank you for sharing your knowledge. It helps a lot.

Our Cicso tech person (the company that installed our system) wanted to charge us $600 to install the Linksys Wireless as part of our network. I'm not saying that techs can't make a living, but when I discovered that it was basically as simple as plugging it in, I got a little hot under the collar. I'm sure the tech would have had all the answers I was looking for but I'm glad I did some of my own sleuthing to save $600. Can I buy ya a cup of coffee :-)

You'll have to address the linksys to the 10.10.10/24 range or address the cisco to the 192.168.1/24 range.

This gets a bit tricky. There's a few ways to accomplish this.

1) Connect the wan device to the linksys and the connect the cisco to that. 2) Nat the wireless network to the lan. Configure the default route on the linksys and a static route to the 10.10.10/24 range to forward such traffic to the cisco and then block the traffic there. Not sure how the linksys would react to a static route to a directly connected network. 3) Use a nat router between the wireless and the lan that is capable of filtering. 4) Use a bridging firewall between the wireless and lan. Configuration would likely be difficult.

Actually, it's a simple implementation and you should be able to call Cisco Thec Support without some one showing on site and let them help you over the phone. Surely, that cannot cost $600.

Duane :)