Multiple APs
Overview
Experimental
Many users have asked if it's possible to create a second wireless access point on the same device. The answer is "yes" with an AP-capable external wireless adapter and the correct settings. The Edimax EW-7811Un USB adapter works without additional drivers on many devices, including the Raspberry Pi. For this reason it is used in this walkthrough.
Tip
We strongly recommend this resource which lists USB WiFi adapters with in-kernel Linux drivers. These will work out of the box on Debian-based devices without installing third-party drivers. You may also wish to skip directly to this short list of "superstar" USB WiFi adapters for Linux. Pay special attention to those that are excellent choices for 5 GHz AP mode, if this is desired.
Scenario
In this setup, we will use an external Edimax 2.4GHz USB adapter together with the onboard wireless chipset of the Raspberry Pi 4 operating on the 5GHz band. The end result is displayed in the WiFi network scan below.
It is not currently possible to create this setup with RaspAP's UI, so these manual steps are provided below. We can, however, leverage the web UI to create the hostapd configurations we'll need.
Prerequisites
This tutorial assumes that you have followed the Quick start or manual installation instructions. If an 802.11 AC 5GHz wireless mode is desired with the RPi's onboard chipset, you must first configure a country that permits wireless operation on the 5GHz band. Refer to this FAQ for more information.
Create the hostapd configs
The simplest method to achieve this is to use RaspAP's Hotspot > Basic tab to create the base configurations. Configure an AP for the onboard wlan0 interface with the settings shown below. Choose Save settings to write this to the filesystem.
Open your preferred terminal program and enter the following command to copy this as a new wlan0 configuration:
sudo cp /etc/hostapd/hostapd.conf /etc/hostapd/wlan0.conf
Next, configure a second AP for the external wlan1 interface with the settings shown below. Again, choose Save settings to write this to the filesystem.
Enter the following command to copy this as a new wlan1 configuration:
sudo cp /etc/hostapd/hostapd.conf /etc/hostapd/wlan1.conf
Tip
If you decide to create two APs on the same band, for example 802.11n 2.4GHz, be sure to select two different channels for each interface.
Configure dnsmasq
RaspAP's default settings includes a preconfigured wlan0 file for the dnsmasq service. Execute cat /etc/dnsmasq.d/090_wlan0.conf to display its contents:
# RaspAP wlan0 configuration
interface=wlan0
domain-needed
dhcp-range=10.3.141.50,10.3.141.254,255.255.255.0,12h
Next, we will copy this file and make some modfications to it:
sudo cp /etc/dnsmasq.d/090_wlan0.conf /etc/dnsmasq.d/090_wlan1.conf
sudo nano /etc/dnsmasq.d/090_wlan1.conf
Edit this file so it looks like the example below, then save it and exit your editor.
# RaspAP wlan1 configuration
interface=wlan1
domain-needed
dhcp-range=10.4.141.50,10.4.141.254,255.255.255.0,12h
Configure dhcpcd
Similar to dnsmasq, the dhcpcd service is preconfigured with RaspAP's default settings. Open this file in an editor by executing sudo nano /etc/dhcpcd.conf, then add a wlan1 block to the end of the file:
# RaspAP default configuration
hostname
clientid
persistent
option rapid_commit
option domain_name_servers, domain_name, domain_search, host_name
option classless_static_routes
option ntp_servers
require dhcp_server_identifier
slaac private
nohook lookup-hostname
# RaspAP wlan0 configuration
interface wlan0
static ip_address=10.3.141.1/24
static routers=10.3.141.1
static domain_name_server=9.9.9.9 1.1.1.1
# RaspAP wlan1 configuration
interface wlan1
static ip_address=10.4.141.1/24
static routers=10.4.141.1
static domain_name_server=9.9.9.9 1.1.1.1
Note
RaspAP only manipulates /etc/hostapd/hostapd.conf so your custom hostapd configs won't be touched. The version 2.6 release lets you manage the dhcpcd and dnsmasq configs from the UI, while also preserving any manual changes.
Finally, enable the Log DHCP requests toggle on RaspAP's DHCP Server > Logging tab. Be sure to restart the dnsmasq service.
Starting the hotspots
Ensure that hostapd is not already running before proceeding. You may stop the service with sudo systemctl stop hostapd.service or by using the Stop hotspot button in RaspAP's UI.
Now we are ready to run hostapd interactively with the configurations we've created above. The debug switch -dd is optional but useful for troubleshooting:
sudo hostapd -dd /etc/hostapd/wlan0.conf /etc/hostapd/wlan1.conf
Connect clients to each AP and monitor the output. You may stop hostapd from the terminal with the Ctrl+C keystroke. Alternatively, you may send the process to the background with Ctrl+Z and restore it to the foreground with fg.
Troubleshooting
With RaspAP's DHCP logging option enabled, it can be useful to monitor this service's activity from the terminal. Execute tail -f /tmp/dnsmasq.log and try associating and disconnecting client devices from each AP.