In the course of helping someone out on Reddit about their setup, it occurred to me that there have been multiple instances of people asking about using an old router as an access point. It also helps if you consider the advice peppered with multiple VLANs and multiple SSIDs. Lets assume you have a Wi-Fi router and want to use another router as an access point (lets call it AP). Further, lets assume that you have two VLANs you wish to use. Here are some things to consider (not in any particular order):
- You probably will want to do a Wi-Fi survey to see where your neighbors are parked on the Wi-Fi spectrum and figure out from there how you want to minimize interference - I recommend Acrylic Wi-Fi as the tool to use, there is a free version. There are also some tools under Kali Linux as well.
- If you have a mobile device, you will generally want to seamlessly switch between Wi-Fi sources. To do this, you are going to want to have the Wi-Fi router and AP on different Wi-Fi channels. So, as a general rule walking around your house will cause your cell phone to connect to the Wi-Fi source with the strongest signal. If on the other hand the one SSID is on the same Wi-Fi channel on both devices you could wind up with them interfering with each other.
- We will assume you have VLANs that you are using to separate the networks.
- I make it a point to have different SSIDs based on the vlan it is connected to, so if you have 2 VLANs, you should use 2 SSIDs (different names).
- Always make sure that the SSIDs have the same passphrase across the devices, but use two different passphrases for two different SSIDs. Then the SSIDs will be cryptographically separate from each other.
- Most smart home devices will use the 2.4GHz spectrum, rarely will you see it connect to 5.4GHz, so you could in effect only need the 2.4GHz spectrum for the smart devices and that may influence your choice for how you set up each SSID.
- If you have smart TVs, I would try to use Ethernet as much as is possible to connect them; video chews up a lot of Wi-Fi bandwidth.
- Don't setup the AP in bridge mode; that implies that you are going through the WAN port. There is no need to do that if you are using it as an access point. Connect the cable from a port on LAN side of the router to one of the ports on the Linksys LAN side. This cable should be designated as a trunk line, i.e. it will be carrying multiple VLANs. By doing it that way, you will keep the one SSID to one vlan mantra unaltered. Setup the VLANs accordingly.
- In the AP vlan setup do not setup a DHCP server, but use a DHCP relay mode instead, and point the relay address to the router vlan IP address. That way a connection to the AP will use the router to get it's IP address (which also means it will get it's DNS info from the same source).
This is simple but effective and I have used this approach many times to success.
