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CloudFlare Dynamic DNS Shell Script
#!/bin/sh
#
# CloudFlare Dynamic DNS
#
# Updates CloudFlare records with the current public IP address
#
# Takes the same basic arguments as A/CNAME updates in the CloudFlare v4 API
# https://www.cloudflare.com/docs/client-api.html#s5.2
#
# Use with cron jobs etc.
#
# e.g.
#
# manually run:
# cloudflare_dyn_dns.sh -key 404613183ab3971a2118ae5bf03d63e032f9e -email test@example.com -zone example.com -name extra
#
# cronjob entry to run every 5 minutes:
# */5 * * * * /path/to/cloudflare_dyn_dns.sh -key 404613183ab3971a2118ae5bf03d63e032f9e -email test@example.com -zone example.com -name extra >> /path/to/cloudflare_dyn_dns.log
#
# will both set the type A DNS record for extra.example.com to the current public IP address for user test@example.com with the provided API key
key=
email=
zone=
zone_id=
type=A
rec_id=
name=
content=
ttl=1
proxied=false
while [ "$1" != "" ]; do
case $1 in
-key ) shift
key=$1
;;
-email ) shift
email=$1
;;
-zone ) shift
zone=$1
;;
-zone_id ) shift
zone_id=$1
;;
-type ) shift
type=$1
;;
-rec_id ) shift
rec_id=$1
;;
-name ) shift
name=$1
;;
-content ) shift
content=$1
;;
-ttl ) shift
ttl=$1
;;
-proxied ) shift
proxied=$1
;;
* ) echo "unknown parameter $1"
exit 1
esac
shift
done
if [ "$content" = "" ]
then
content=`curl -s http://myexternalip.com/raw`
if [ "$content" = "" ]
then
date
echo "No IP address to set record value with."
exit 1
fi
fi
if [ "$name" = "" ]
then
echo "You must provide the name of the record you wish to change."
exit 1
fi
if [ "$zone" = "" ]
then
echo "You must provide the domain you wish to change."
exit 1
fi
existing_content=`host -t $type $name.$zone | sed -E 's/.+?\s+([^\s]+)$/\1/'`
if [ "$content" = "$existing_content" ]
then
echo "Existing record value $existing_content is the same as provided content $content. Exiting."
exit
fi
if [ "$key" = "" ]
then
echo "You must provide your user API token."
exit 1
fi
if [ "$email" = "" ]
then
echo "You must provide your user email."
exit 1
fi
# Get the zone id for the entry we're trying to change if it's not provided
if [ "$zone_id" = "" ]
then
zone_response_json=`curl -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json"`
zone_id=`echo $zone_response_json | sed -E "s/.+\"result\":\[\{\"id\":\"([a-f0-9]+)\"[^\}]+$zone.+/\1/g"`
if [ "$zone_id" = "" ]
then
echo "Cloudflare DNS Zone id could not be found, please make sure it exists"
exit 1
fi
fi
# Get the record id for the entry we're trying to change if it's not provided
if [ "$rec_id" = "" ]
then
rec_response_json=`curl -X GET "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records?name=$name.$zone" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json"`
rec_id=`echo $rec_response_json | sed -E "s/.+\"result\":\[\{\"id\":\"([a-f0-9]+)\"[^\}]+\"type\":\"$type\"[^\}]+$name.$zone.+/\1/g"`
if [ "$rec_id" = "" ]
then
echo "Cloudflare DNS Record id could not be found, please make sure it exists"
exit 1
fi
fi
# Update the DNS record
update_response=`curl -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_id/dns_records/$rec_id" -H "X-Auth-Email: $email" -H "X-Auth-Key: $key" -H "Content-Type: application/json" --data "{\"id\":\"$rec_id\",\"type\":\"$type\",\"name\":\"$name.$zone\",\"content\":\"$content\",\"ttl\":\"$ttl\",\"proxied\":$proxied}"`
success_val=`echo $update_response | sed -E "s/.+\"success\":(true|false).+/\1/g"`
if [ "$success_val" = "true" ]
then
echo "Record Updated."
else
echo "Record update failed."
exit 1
fi
@anshgh
anshgh commented Aug 22, 2014

Thank you!
script works:
[root @ router1 sbin] # /etc/rc.d/cf_eth0.sh
Attempting to get current public IP Address for content.
Record Updated.

But I there are several IP addresses. How can I update a specific (one of the four IP)?

@anshgh
anshgh commented Aug 25, 2014

add "content=" )))

@chappy84
Owner

Hi @anshgh

apologies for the delayed response.

You are quite correct, using an command line argument of '-content 8.8.8.8' will ensure the script ignores the current public IP address and sets the content of the DNS record to 8.8.8.8
The script was originally only intended for boxes with one public IP address, hence defaulting to the public IP address of whichever is the default network adapter

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