[SOLVED] Connecting 2 Routers to use 1 as Guest Wifi Network

[TheDudestPriest]

Hi yall, how yall doing this evening?

Here is my situation, I just signed up with Spectrum Internet (400 Mbps package) and the router they sent me, a Sagemcom Wave 2, doesn't have an option to enable a Guest network, so what I would like to do is connect an older Spectrum router, that I had laying around for a while which is a Sagemcom Fast 5260 to the man Wave 2 to set up as my Guest WuFi network, for when I have people over. Yes, I know it would be easier to go out and buy my own router that has this feature, but at the present moment I'm just not able to.


If anyone can explain to me how to do this or if it is even possible with these 2 routers, I'd be greatly appreciated.

Thank yall and have a great night,
TheDudestPriest

 

[SamirD]

Sure, really easy.

First, you'll want to just connect a laptop/computer to the old Sagemcom Fast 5260 lan port and make sure nothing else is plugged in. You will need to log into the Sagemcom Fast 5260 and change the dhcp range on the modem to something different than what you are using on the newer wave 2. For example, 192.168.2.x versus 192.168.1.x. Once you do this, it will probably need to reboot.

Once rebooted, reconnect to the Sagemcom Fast 5260 and confirm the dhcp range is now different than the newer wave 2. Set up your access points in the Sagemcom Fast 5260 how you would like them for the guest network and test that your laptop or other wifi device can connect to the Sagemcom Fast 5260.

Once you have this working, you now just need to connect the Sagemcom Fast 5260 wan port to the wave 2 lan port and the Sagemcom Fast 5260 should have an IP address from the wave 2 and should now have internet access. The devices on the Sagemcom Fast 5260 will be able to see things on your wave 2 network, but shouldn't be able to access things like network shares because of the nat firewall on the Sagemcom Fast 5260. It's not a perfect vlan type of guest network setup, but it's about as good as it gets unless you have a dmz on the wave 2 that is isolated from the lan, then you can put the Sagemcom Fast 5260 in the dmz and you should be completely solid.

 

[bill001g]

The above method works but it is not clearly pointed out that it also needs a firewall rule to fully work. Note if the sagemcom can not put the rule in your networks will not be secure.

So say your main router uses 192.168.1.x and the guest network uses 192.168.2.x. Because of the default NAT the main network can not initiate a session with the guest network. This is ok but not your main concern. Guest network can still open sessions with the main network because from its viewpoint it is the internet.

So you need a rule in the sagemcom router that says traffic from 192.168.2.x to 192.168.1.x is not allowed.

 

[SamirD]

The above method works but it is not clearly pointed out that it also needs a firewall rule to fully work. Note if the sagemcom can not put the rule in your networks will not be secure.

So say your main router uses 192.168.1.x and the guest network uses 192.168.2.x. Because of the default NAT the main network can not initiate a session with the guest network. This is ok but not your main concern. Guest network can still open sessions with the main network because from its viewpoint it is the internet.

So you need a rule in the sagemcom router that says traffic from 192.168.2.x to 192.168.1.x is not allowed.

I forgot about fixing this with a static route. Good call. That is if the router can even do static routes as many isp units today can't.