cloudflare-ddns.sh

#/usr/bin/env sh

# Get the Zone ID from: https://www.cloudflare.com/a/overview/<your-domain>
DNS_ZONE=***

# Get the existing identifier for DNS entry:
# https://api.cloudflare.com/#dns-records-for-a-zone-list-dns-records
IDENTIFIER=***

# Get these from: https://www.cloudflare.com/a/account/my-account
AUTH_EMAIL=***
AUTH_KEY=***

# Desired domain name
DOMAIN_NAME="***"

# Get previous IP address
_PREV_IP_FILE="/tmp/public-ip.txt"
_PREV_IP=$(cat $_PREV_IP_FILE)

# Curl fritzbox public IP
_IP=$(curl "http://192.168.1.1:49000/igdupnp/control/WANIPConn1" \
  -H "Content-Type: text/xml; charset="utf-8"" \
  -H "SoapAction:urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIPAddress" \
  -d "<?xml version='1.0' encoding='utf-8'?> <s:Envelope s:encodingStyle='http://schemas.xmlsoap.org/soap/encoding/' xmlns:s='http://schemas.xmlsoap.org/soap/envelope/'> <s:Body> <u:GetExternalIPAddress xmlns:u='urn:schemas-upnp-org:service:WANIPConnection:1' /> </s:Body> </s:Envelope>" \
  -s | grep -Eo '\<[[:digit:]]{1,3}(\.[[:digit:]]{1,3}){3}\>')
#_IP=$(curl --silent https://api.ipify.org)
echo $_IP
# If new/previous IPs match, no need for an update.
if [ "$_IP" = "$_PREV_IP" ]; then
    exit 0
fi

echo $_IP

_UPDATE=$(cat <<EOF
{ "type": "A",
  "name": "$DOMAIN_NAME",
  "content": "$_IP",
  "ttl": 120,
  "proxied": true }
EOF
)

curl "https://api.cloudflare.com/client/v4/zones/$DNS_ZONE/dns_records/$IDENTIFIER" \
     --silent \
     -X PUT \
     -H "Content-Type: application/json" \
     -H "X-Auth-Email: $AUTH_EMAIL" \
     -H "X-Auth-Key: $AUTH_KEY" \
     -d "$_UPDATE" > /tmp/cloudflare-ddns-update.json && \
     echo $_IP > $_PREV_IP_FILE