Wiki.Cyli.Org

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==== This is the script I use to keep the dynamic DNS in sync. ====
<code bash Afraid.Org_update.sh>
#!/bin/sh
# /usr/local/bin/Afraid.org.update.sh
# Run me to set the external address up
#
# SRJ 2011-03-12 Initial build
# SRJ 2012-12-10 Modified first wget line for new router
# SRJ 2017-05-03 Updated the IP test again, IP Chicken is being weird
# SRJ 2025-02-04 Verified this still works as expected, and spell check.
# 
#   A note about Cincinnati Bell/AltaFiber - I have records of address changes
#   going back to 2017-04-30 and as of 2025-02-04, my external address has 
#   only changed 49 times. That includes two moves and at least one server 
#   rebuild, plus the change in billing. I get amazing service from these
#   folks at a reasonable cost. Currently getting about 680MBS Down and 640
#   Up, with a Max delay of 3ms connecting to Netflix servers;
#     https://stevejonescomputers.com/SpeedTest.png
#     This is tested using Sindre Sorhus' fast-cli
# 
# -  -  -  -  8< -  -  -  -  - >8  -  -  -  -
# This should be used from cron as below;
#   root@home:~$ crontab -l
#   # .---------------- minute (0 - 59) 
#   # |  .------------- hour (0 - 23)
#   # |  |  .---------- day of month (1 - 31)
#   # |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ... 
#   # |  |  |  |  .---- day of week (0-6) (Sun=0) OR sun,mon,tue,wed,thu,fri,sat 
#   # |  |  |  |  |
#   # *  *  *  *  *  command to be executed
#   */10 *  *  *  * /usr/local/bin/Afraid.org.update.sh  # Run every ten minutes
# -  -  -  -  8< -  -  -  -  - >8  -  -  -  -
# 
# Make sure that anybody or thing can read the Logfile
# (In my environment, this is fine, ymmv)
umask 000
Logfile=/var/log/Afraid.org.log
# Once the log file is created with open permissions, this script can and should
# be run as a regular user.


# The variable 'Current' needs to be modified if you aren't getting
# a proper IP address in it.
# This sometimes failed to report, giving a nul that then triggered
# an un-needed update.
# Current=$(
# wget -q -O- "http://checkip.dyndns.org/" \
# | grep -o -E "([0-9]{1,3}[\.]){3}[0-9]{1,3}"
# )

# Let's give this a try for a while!
Current=$(
dig @resolver4.opendns.com myip.opendns.com +short -4
)
# Or 
# dig @resolver3.opendns.com myip.opendns.com +short
# dig @ns1-1.akamaitech.net ANY whoami.akamai.net +short
# curl -s http://whatismyip.akamai.com/ && echo

# Present the date in an easily grepable fashion.
Date=$(
	date +"%Y-%m-%d-%H-%M"
	)

# If the Logfile doesn't exist, create it with a known IP address.
if [ ! -f $Logfile ] ; then
	echo "${Date} 0.0.0.0" >> ${Logfile}
	fi

# If the Logfile still does not exist, something is wrong, cry for help.
if [ ! -f $Logfile ] ; then
        echo "Cannot create ${Logfile} - check directory permissions"
        exit 1
	fi

# What was our IP address the last time it changed? 
Last=$(
	tail -1 ${Logfile} | cut -d " " -f 2
	)

# If our current IP is the same as it was at last change, then there 
# isn't any reason to contact Afraid.org, just die with grace.
if [ "${Current}" = "${Last}" ] ; then # No update is required, silently exit.
	exit 0
	fi

echo "Update of external IP address needed."
echo "${Date} ${Current}" >> ${Logfile}
# The line below is from afraid.org and is what actually sets the DNS entries
# for the domain. Make sure you have a valid string for a domain you own!
wget -q --read-timeout=0.0 --waitretry=5 --tries=400 -O- \
https://freedns.afraid.org/dynamic/update.php?ZHA5bbbNotARealThingdddTk3xWk5yeVI6MjIwNjI0MzA=
</code>