Cascading gateway routers and other theory (Netgear, SMC)

[velusip]

I've been using a Netgear router for nearly a decade now and it works beautifully. I needed to add some wireless to the mix. I didn't want to have to switch to anything else, but the pain that this Orinoco AP has caused me made me go buy a preconfigured wireless router...

I purchased an SMC wireless router because of the lack of compatibility issues with the wireless among friends. It's true, no problems whatsoever with the wireless. It even cascades off the Netgear, however DHCP is completely destroyed and since the wireless features cease to work once you disable DHCP as well, it's pretty much completely useless. I don't want to flip the routers around either since the netgear does a much better job of port forwarding through NAT. Basically the Netgear is way better, and I don't want to completely phase it out.

I was wondering if instead of cascading the SMC as a switch, could I simply plug the WAN port of the SMC into one of the DHCP distributed ports of the Netgear? I've wondered this for a long time, but never bothered trying it.

It would look a little like this:

Netgear RT314 (WAN: x.x.x.x, LAN: 192.168.0.1)
SMC WBR14T-G (WAN: 192.168.0.2, LAN: 192.168.2.1)

I'm about to try it, but I figured perhaps someone out there has done this and could give me some tips. Perhaps if I should disable RIP among other things on the SMC. Tips welcome!

 

[versello]

You don't have to disable RIP or any of that junk. It's not relevant in this scenario.

While what you want to perform is possible, and probably the cheapest and reccomended way to go in your scenario, I advise against "double NAT-ing".

 

[YeOldeStonecat]

Agree...double NAT'ing...you want to stay away from this. By double NAT'ing, I mean...connecting 2x routers in such a way that the inside routers WAN port connects to a LAN port of the outside router. Even when setup optimally, meaning obviously you need to have each router on a different IP scope, "most things" work OK, like internet browsing. But some applications will hate it because of the way home grade routers handle NAT, and that inadequacy shows up with double NAT'ing home routers.

By different IP scope, that means you cannot have both routers doing 192.168.1.XXX or whatever. That 3rd octect must be different, such as outside router on 192.168.0.1, and inside router on 192.168.1.1...something like that.

If you have a router, what you really wanted to get was an access point, not another router.

However, since you got this router, you can bandaid things to work as an access point.
Some routers (like Belkin routers) have a feature you see in their web admin, to run in either gateway mode, or access point mode. This is a cool feature. However most wireless router brands do not have this feature...so you have to McGuyver it yourself with duct tape and paperclips.

First, (having your wireless router NOT connected to your main network, but plug one computer into it such as a laptop) assign the wireless router a static IP address in the same range as your main router, but obviously a unique IP. One that's outside the DHCP hand out range of the main router. So if your main router is 192.168.0.1, make your wireless router something like 192.168.0.253, or 192.168.0.2. Reboot (or just release/renew) your system connected to it.

Next....disable DHCP on the wireless router.

Next..NOW you can connect your wireless router to your main network...however...do NOT use the WAN port of the wireless router, instead...uplink it to your main network using one of the LAN ports. Depending on yoru routers...if they support auto direction on the ports, or if one of them uses an "uplink" port...or if none of the above, you might need a crossover cable. Either way...you want LAN port of Netgear to link to LAN port of SMC.
Now try to access the web admin of the SMC from a computer plugged into your main network...should be able to bring it up with no problem, and computers should be fine to setup on the WLAN now.

 

[ktwebb]

I'm confused as why you would think you'd need to disable RIP. It's the other way around if you want the SMC to route. The primary router would need to talk RIP as well, to the SMC router.

Frankly I don't know why you would want the thing to route anyway unless you want to segment that network from your first one. Instead of the WAN port you'd uplink the switch on the SMC. Disabling DHCP which it sounds like you've done already. That doesn't break the router by the way. Disabling DHCP does one thing, it stops accepting DHCP requests from clients. That's it. If you use static IP's on the clients then there's no problem. Anyway, by uplinking the SMC on the LAN side you now have a few extra wired ports and an AP at your disposal, all on the original network.

Having said all that, if your first router supports RIP then you would not be doing double NAT. If you disabled RIP then the second router would try to NAT the address on that side of the LAN. For RIP, it's true, you'd need to make sure the second network has a different network ID than the first but the two routers would be doing RIP routing, not NAT routing. It's just not worth the hassle when it's unnecessary.

Just eliminate any kind of routing on the SMC. It becomes a switch/AP combo. Pretty common scenario and has been for almost as long as these devices have been around.

 

[velusip]

So it's doable. Excellent.

I supposed I didn't make it very clear, but here's why I asked:

SMC -> DHCP off, in cascade (or uplinked), no wireless. It just stops working.

Of course switching the responsibilities around would work (having the SMC do DHCP so wireless works), but then what's the point of cascading? I need the Netgear where it is because it does a much better job of taking names and kicking ass (NAT). I know you all hate me for praising Netgear, but seriously, this thing is old and won't die.

So rather than cascading, adding yet another hop to the mix and providing an "AP" alternative works best. Thanks for your help folks!