Chk-WAN

ASUS Router Check WAN status

This script can monitor the connection status of a WAN interface, and if the status is found to be unacceptable, can perform one of the following:

  1. Report the status of the WAN connection.
  2. Attempt to restart the WAN interface.
  3. REBOOT the router.

The monitoring method is either

1. A simple PING to 5 predefined target PING hosts

   ISP WAN_gateway
   ISP_DNS 		x 2
   8.8.8.8			(Google Primary DNS)
   1.1.1.1			(Cloudflare Primary DNS)
   
   or a custom list of WAN PING targets e.g. ping=9.9.9.9,185.228.168.9 (Quad9 Primary DNS, Clean Browsing Primary)
   

2. A cURL data transfer retrieval from the WAN - either a 15 Byte (default) or either a ~500 Byte or 12MB.

   **Beware if using a metered connection!**
   
   Optionally an expected transfer rate may be specified to perform the desired action if the transfer is deemed slow.
   

NOTE: Only one of the test criteria needs to succeed, i.e. if 5 PING hosts are used, the test will terminate with the first successful host that responds to the PING - ignoring the others.

To prevent transient false positives, the number of retries and a maximum number of fails permitted for each method defaults to retries=3 and fails=3, and be tailored e.g. retries=1 fails=1 whilst the result being immediate, may seemingly fail, due to the PING or cURL target entity being briefly unavailable

The complete list of command options may be retrieved using

ChkWAN.sh   help

============================================================================================ © 2016-2018 Martineau v1.11

Monitor WAN connection state using PINGs to multiple hosts, or a single cURL 15 Byte data request and optionally a 12MB/500B WGET/CURL data transfer.
	NOTE: The cURL data transfer rate/perfomance threshold may also be checked e.g. to switch from a 'slow' (Dual) WAN interface.
	Usually the Recovery action (REBOOT or restart the WAN) occurs in about 90 secs (PING ONLY) or in about 03:30 mins for 'force' data download

Usage: ChkWAN  [help|-h]
               [reboot | wan | noaction] [force[big | small]] [nowait] [quiet] [once] [i={[wan0|wan1]}] [googleonly] [curl] [ping='ping_target[,..]'] 
               [tries=number] [fails=number] [curlrate=number]

       ChkWAN
               Will REBOOT router if the PINGs to ALL of the hosts FAILS
       ChkWAN  force
               Will REBOOT router if the PINGs to ALL of the hosts FAIL, but after each group PING attempt, a physical 12MByte data download is attempted.
       ChkWAN  forcesmall
               Will REBOOT router if the PINGs to ALL of the hosts FAIL, but after each group PING attempt, a physical 500Byte data download is attempted.
               (For users on a metered connection assuming that the 15Byte cURL is deemed unreliable?)
       ChkWAN  wan
               Will restart the WAN interface (instead of a FULL REBOOT) if the PINGs to ALL of the hosts FAIL
       ChkWAN  curl
               Will REBOOT router if cURL (i.e. NO PINGs attempted) fails to retrieve the remote end-point IP address of the WAN (Max 15bytes)
       ChkWAN  cron
               Will REBOOT router if the PINGs to ALL of the hosts FAILS, cron entry is added: Runs every 5mins.
               'cru a ChkWAN "*/5 * * * * /jffs/scripts/ChkWAN.sh"'
       ChkWAN  nowait
               By default the script will wait 10 secs before actually starting the check; 'nowait' (when used by cron) skips this delay.
       ChkWAN  googleonly
               Only the two Google DNS severs will be PING'd - WAN Gateway/local DNS config will be ignored
       ChkWAN  i=wan1 noaction
               In a Dual-WAN environment check WAN1 interface, but if it's DOWN simply return RC=99
       ChkWAN  ping=1.2.3.4,1.1.1.1
               PING the two hosts 1.2.3.4 and 1.1.1.1, rather than the defaults.
       ChkWAN  tries=1 fails=1
               Reduce the number of retry attempts to 1 instead of the default 3 and maximum number of fails is 1 rather than 3
       ChkWAN  force curlrate=1000000
               If the 12MB average curl transfer rate is <1000000 Bytes per second (1MB), then treat this as a FAIL

Installation

Enable SSH on router, then use your preferred SSH Client e.g. Xshell6,MobaXterm, PuTTY etc. to copy'n'paste:

curl --retry 3 "https://raw.githubusercontent.com/MartineauUK/Chk-WAN/master/ChkWAN.sh" -o "/jffs/scripts/ChkWAN.sh" && chmod 755 "/jffs/scripts/ChkWAN.sh"

You can manually test the script with the default PING method, and the script will simply passively report the status, rather proactively restart the WAN or REBOOT

./ChkWAN.sh noaction once nowait

but for automated monitoring, you would include the call to the script in

/jffs/scripts/wan-start

sh /jffs/scripts/ChkWAN.sh &

or use cru (cron) to schedule the script at a pre-determined scheduled time) NOTE: You could configure the cron schedule such that the scipt will restart the WAN say 3 times, but every fourth attempt will action the REBOOT.