Server Mode
Great for use in a network lab
Server mode is a great way of turning the WLAN Pi into a box of tricks that can provide many of the network services that you'll need for a home or small scale lab.
If you flip your WLAN Pi into Server mode, you'll instantly have access to a:
DHCP server
TFTP server
Wireless Console
As we've already covered the Wireless Console functionality in a previous demo, we take a look at using and configuring the DHCP and TFTP servers.
Please review the caveat below.
When switching the WLAN Pi into Server mode, a DHCP server becomes available on the Ethernet port of the WLAN Pi. If it is connected to a network port already supplies IP address via DHCP, this may cause a conflicts and service issues for other devices on the same segment.
Make sure you do not connect the WLAN Pi in Server mode to a customers network segment which already has a DHCP service configured!
Server Mode
To switch into server mode, select the mode from the FPMS menu option:
Modes > Server > Confirm
The WLAN Pi will now reboot and switch into Server mode.
Note that unlike other WLAN Pi modes, Server mode is not persistent.
When the WLAN Pi is rebooted or powered off/on, it will automatically revert to Classic mode.
This behavior is to prevent it being accidentally being booted up in Server mode on a live network (see DHCP server caveat above).
DHCP Server
Once the WLAN Pi is in Server mode, a DHCP service is available on the Ethernet port of the WLAN Pi. If you connect this to a lab switch VLAN, it provides a quick and easy way of providing IP addresses to your lab devices.
It's very easy to modify the service to provide the IP range, DNS servers and DHCP options that you need. This makes it an excellent tool for tasks such testing or staging APs that have custom DHCP option requirements.
The configuration files for the DHCP service can be found in the file dhcp.conf
in the directory /etc/wlanpi-server/dhcp/
. The screenshot below shows how to access the configuration file and list its contents:
If you'd like to change any aspect of the DHCP scope before switching into Server mode (e.g. DNS servers, lease time etc.), edit this file using an editor such as "nano" before the mode switch. When you switch from Classic to Server mode, the configuration file will be read and your new DHCP configuration used for the DHCP service.
If you'd like to add in a custom option for your APs to direct them to a specific wireless controller (e.g. option 43), then take a look at: https://www.jiribrejcha.net/2020/08/cisco-aironet-and-catalyst-ap-option-43-configuration-for-isc-dhcp-server-on-linux/
TFTP Server
Server mode also comes with pre-configured TFTP server.
It is useful for firmware and software upgrades. Home folder of the TFTP server is /srv/tftp
.
Upload your software image to the folder above on your WLAN Pi, SSH to the device you are upgrading, and initiate the upgrade from the device.
Here is an example of Cisco AP manual image upgrade:
TFTP is also useful when you want to backup configurations, logs, or tech support dumps from your network devices. You could do something along these lines and save your switch configuration to the WLAN Pi TFTP server. You will find it in the /srv/tftp
folder.
Further Information
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