Monitoring Wireless Access Points running OpenWRT

In my effort to monitor all the things, I found that i needed better reporting from my OpenWRT-based devices. It’s a pretty painless process.

How To

First, hit up ya device using SSH and login.

kurth@wrks:~$ ssh root@192.168.XXX.XXX
root@192.168.XXX.XXX's password: 


BusyBox v1.30.1 () built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 19.07.4, r11208-ce6496d796
 -----------------------------------------------------
root@CTTWAP1:~#

Once logged in, update ensure the package manager is updated

root@CTTWAP1:~# opkg update
Downloading http://downloads.openwrt.org/releases/19.07.4/targets/ath79/generic/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_core
Downloading http://downloads.openwrt.org/releases/19.07.4/targets/ath79/generic/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/targets/ath79/generic/kmods/4.14.195-1-b84a5a29b1d5ae1dc33ccf9ba292ca1d/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_kmods
Downloading http://downloads.openwrt.org/releases/19.07.4/targets/ath79/generic/kmods/4.14.195-1-b84a5a29b1d5ae1dc33ccf9ba292ca1d/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/base/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_base
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/base/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_luci
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/luci/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_packages
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_routing
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/routing/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_telephony
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/telephony/Packages.sig
Signature check passed.
root@CTTWAP1:~# 

Install mini_snmpd

root@CTTWAP1:~# opkg install mini_snmpd
Installing mini_snmpd (1.4-rc1-4) to root...
Downloading http://downloads.openwrt.org/releases/19.07.4/packages/mips_24kc/packages/mini_snmpd_1.4-rc1-4_mips_24kc.ipk
Configuring mini_snmpd.
root@CTTWAP1:~# 

Now we edit the /etc/config/mini_snmpd config file. My completed file looks like this

config mini_snmpd 'default'
        option enabled 1
        option ipv6 0
        option debug 0
        option auth 0
        option community 'public'
        option contact 'Kurth Bemis <kurth@XXXXXXXX.com>'
        option location 'LOCATION NAME HERE'
        option listen_interface 'lan'
        #option udp_port '161'
        #option tcp_port '161'
        #option vendor_oid ''
        option mib_timeout 1
        list disks '/overlay'
        list disks '/tmp'
        list interfaces 'lan'
        list interfaces 'wan'

As you can see, it’s mostly ready to go out of the box. (To exit vi use :wq)

Now we just need to ensure the service is enabled

root@CTTWAP1:~# /etc/init.d/mini_snmpd enable

…and to make sure the daemon is running.

root@CTTWAP1:~# /etc/init.d/mini_snmpd start

To setup monitoring, I pointed LibreNMS to the IP address of the AP. Within a few minutes I had graphs rolling.

Notes

I would normally use snmpd for my snmp needs on Linux/BSD systems and devices, however I had heard good things about mini_snmpd relating to size and speed and it being designed and build for embedded systems. We’ll see how it compares to the standard snmpd.

Resources

https://wiki.kurthbemis.com/index.php?title=Monitoring_Wireless_Access_Points_running_OpenWRT