Set an SSID to bottom of the Preferred Networks List

[cainehorr]

UPDATED ON TUESDAY, AUGUST 27, 2019

In my environment I have two (or more) corporate SSIDs and a single Guest SSID.

During our Jamf enrollment process, in-house devices always start out on the Guest network then they receive a Jamf mobileconfig that grants them access to the various corporate SSIDs.

Historically, the problem has been the fact that new SSIDs tend to automatically go to the bottom of the Preferred Networks stack.

When the device in question reboots, instead of auto-connecting to the Corp network, it instead connects to the Guest network and that's no bueno.

So... I started using reorder_wifi_alt.py . I bit of hacking and I was able to put my Guest SSID at the bottom.

This worked well... for awhile. However, after a few updates for 10.14 (Mojave), the python script stopped working as advertised and since I'm not very proficient with Python, I decided to dive in nose first and attempt to find and/or write my own bash script to do this very task.

Low and behold, after much Googlin' - I found this Jamf Nation article by @jjones... https://www.jamf.com/jamf-nation/discussions/17858/wifi-preference-editing-script

This is exactly what I needed - sort of...

My only problem is... I don't need all that fancy stuff AND I need to go to the bottom of the stack, not the top.

So, I picked out the bare minimum pieces and cobbled together the following hack...

#!/bin/bash

######################################################################
#
# FILENAME: 
#   Set_SSID_Preferred_Network_To_Bottom.sh
#
# DESCRIPTION: 
#   Move Specific SSID to the bottom of the Preferred  Wireless
#   Network Stack.
#
#   It has been tested and does not de-auth the user if they are 
#   currently on the SSID to be changed (If the SSID password remains
#   in the keychain). 
#
#   This works with Network configuration mobileconfigs too.
#
#   This may not work with 802.1x - More testing needs to be done.
#
# CREDITS: 
#   Inspired by https://www.jamf.com/jamf-nation/discussions/17858/wifi-preference-editing-script
#
######################################################################
#
# CHANGE CONTROL LOG
#   Version 2.0 - 2019-08-27
#       Updated by Caine Hörr
#           * Broke script out into functions
#           * Updated to identify number of preferred wireless networks
#           * Updated to include a secondary SSID to move
#           * Added logic to test if SSIDs are listed
#
#   Version 1.0 - 2019-05-30
#       Written by Caine Hörr
#           * Initial script creation
#           * Tested against macOS 10.14.4 (Mojave)
#
# POSSIBLE FUTURE UPDATES
#   * Quit System Preferences in case it's open... Just in case...
#   * Do some error checking for older macOS versions (ie WiFi vs 
#       AirPort)
#   * Do some cool array stuff... count in number of existing SSIDs
#       to determine the actual priority number...
#
######################################################################

######################################################################
# USER DEFINED SETTINGS
######################################################################

# SSID values to move to the bottom of the preferred wireless network stack
# SSID Values are case sensitive
SSID_Second_From_Bottom="Lab"     # SSID to be placed second from the bottom of the preferred wireless network list
SSID_Bottom="Guest"           # SSID to be placed on the bottom of the preferred wireless network list

# Set the Wireless Security Type (ie WPA, WPA2, etc.)
WirelessSecurity_Second_From_Bottom="WPA2"
WirelessSecurity_Bottom="WPA2"

######################################################################
# NO USER SERVICEABLE PARTS BELOW THIS LINE
######################################################################

main(){
    Acquire_Network_Details
    Bottom_SSID
    Second_From_Bottom_SSID
    List_Preferred_Wireless_Networks
}


Acquire_Network_Details(){
    # Automatically determine the WiFi Interface (ie en0)
    NetworkPort=$(/usr/sbin/networksetup -listallhardwareports | /usr/bin/grep -A 1 Wi-Fi | /usr/bin/grep Device | /usr/bin/cut -d' ' -f2)
    echo "Network Interface: ${NetworkPort}"

    number_of_preferred_wireless_networks=$(/usr/sbin/networksetup -listpreferredwirelessnetworks ${NetworkPort} | /usr/bin/sed '1d' | /usr/bin/wc -l | /usr/bin/awk '{$1=$1;print}')
    number_of_preferred_wireless_networks=$(expr ${number_of_preferred_wireless_networks} - 1)
    echo "Number of Preferred Wireless Networks: ${number_of_preferred_wireless_networks}"
}

Bottom_SSID(){
    echo ""
    # Confirm existence of SSID_Bottom
    existence_of_SSID=$(/usr/sbin/networksetup -listpreferredwirelessnetworks en0 | /usr/bin/awk '{$1=$1;print}' | /usr/bin/grep -Fx "${SSID_Bottom}")
    echo "SSID To Test: ${SSID_Bottom}"

    if [ "${existence_of_SSID}" = "${SSID_Bottom}" ]; then
        echo "SSID "${SSID_Bottom}" found on this device"

        SSID="${SSID_Bottom}"
        WirelessSecurity="${WirelessSecurity_Bottom}"

        # Define the postion of the bottom preferred wireless network
        Position=${number_of_preferred_wireless_networks}

        Reorder_Preferred_Wireless_Network_Stack
    else
        echo "SSID "${SSID_Bottom}" not found on this device"
    fi
}

Second_From_Bottom_SSID(){
    echo ""
    # Confirm existence of SSID_Second_From_Bottom
    existence_of_SSID=$(/usr/sbin/networksetup -listpreferredwirelessnetworks en0 | /usr/bin/awk '{$1=$1;print}' | /usr/bin/grep -Fx "${SSID_Second_From_Bottom}")
    echo "SSID To Test: ${SSID_Second_From_Bottom}"

    if [ "${existence_of_SSID}" = "${SSID_Second_From_Bottom}" ]; then
        echo "SSID "${SSID_Second_From_Bottom}" found on this device"

        SSID="${SSID_Second_From_Bottom}"
        WirelessSecurity="${WirelessSecurity_Second_From_Bottom}"

        # Define the position of the second from the bottom preferred wireless network
        Position=$(/bin/expr ${number_of_preferred_wireless_networks} - 1)

        Reorder_Preferred_Wireless_Network_Stack
    else
        echo "SSID "${SSID_Second_From_Bottom}" not found on this device"
    fi
}

Reorder_Preferred_Wireless_Network_Stack(){
    echo ""
    # Remove the SSID from the Preferred Network stack because you can't just move things... You must remove them... Stupid...
    /usr/sbin/networksetup -removepreferredwirelessnetwork "${NetworkPort}" "${SSID}"

    # Re-Add the SSID into the Preferred Network stack at the Priority level indicated
    /usr/sbin/networksetup -addpreferredwirelessnetworkatindex "$NetworkPort" "${SSID}" "${Position}" "${WirelessSecurity}"
}

List_Preferred_Wireless_Networks(){
    /usr/sbin/networksetup -listpreferredwirelessnetworks ${NetworkPort}
}


main

exit

As you can see, it's a fairly straight-forward and lean script.

When the script is run, you should see the following output...

$ ./Set_SSID_Preferred_Network_To_Bottom.sh 
Network Interface: en0
Number of Preferred Wireless Networks: 17

SSID To Test: Guest
SSID "Guest" found on this device

Removed Guest from the preferred networks list
Security type is set to: WPA2 Personal
Added Guest to preferred networks list

SSID To Test: Lab
SSID "Lab" found on this device

Removed Lab from the preferred networks list
Security type is set to: WPA2 Personal
Added Lab to preferred networks list

Preferred networks on en0:
    ahs-guest-wireless
    ATT233CCU2
    Milk Powered
    Sands-Guest
    attwifi
    MRM-DDS public
    #SFO FREE 5GHZ WIFI
    @Hyatt_WiFi
    Ruckus-Wireless-1
    Public
    Sands_WiFi
    Gamma Quadrant
    Google Starbucks
    Alien_Queen
    BATCH & BRINE GUEST
    Lab
    Guest

So anyway - there you have it...

I'm always open to suggestions for improvement.

Hope you find it useful in some fashion!

[sdagley]

@cainehorr I don't believe a Wi-Fi config that uses 802.1x authentication will survive this approach to moving it. Here's a script I came up with, based on one originally posted by pudquick, to handle a variable number of SSIDs that you want promoted to the top of the Preferred Networks list that preserves any 802.1x configuration, and it works on Mojave: Preferred Wireless Network priority

[cainehorr]

@sdagley You may be correct regarding 802.1x configured networks.

I'm working with a few WPA/WPA2 networks, hence the reason for the script.

I've updated the script and include some additional context with regards to the purpose.