cloudflare_dyndns_ipv4_apiv4.sh

#!/bin/bash

cloudflare_email="test@example.com"             # Your Cloudflare email
cloudflare_api_key="API_KEY_HERE"               # Your Cloudflare API key
cloudflare_dns_zone="DNS_ZONE_HERE"             # DNS zone containing the record you want to modify
cloudflare_dyndns_record="home.example.com"     # Name of the record you want to modify

res="$(curl -sS -X GET "https://api.cloudflare.com/client/v4/zones/$cloudflare_dns_zone/dns_records" \
     -H "X-Auth-Email: $cloudflare_email" \
     -H "X-Auth-Key: $cloudflare_api_key" \
     -H "Content-Type: application/json")"

remote_ip="$(echo "$res" | jq ".result[]|select(.name==\"$cloudflare_dyndns_record\").content")"
remote_ip="$(eval echo "$remote_ip")" # Fix quotes in string

local_ip="$(curl -sS -4 icanhazip.com)"

echo "Remote IP: $remote_ip"
echo "Local IP: $local_ip"

if [[ "$remote_ip" == "$local_ip" ]]; then
    echo "IP addresses are the same."
    exit 0
else
    echo "IP addresses differ. Changing remote IP..."
    cloudflare_dyndns_record_zone_id="$(echo "$res" | jq ".result[]|select(.name==\"$cloudflare_dyndns_record\").id")"
    cloudflare_dyndns_record_zone_id="$(eval echo "$cloudflare_dyndns_record_zone_id")" # Fix quotes in string
    if curl -sS -o /dev/null -X PUT "https://api.cloudflare.com/client/v4/zones/$cloudflare_dns_zone/dns_records/$cloudflare_dyndns_record_zone_id" \
            -H "X-Auth-Email: $cloudflare_email" \
            -H "X-Auth-Key: $cloudflare_api_key" \
            -H "Content-Type: application/json" \
            --data '{"type":"A","name":"'$cloudflare_dyndns_record'","content":"'$local_ip'","ttl":120,"proxied":false}'; then
        echo "Successfully updated remote IP."
        exit 0
    else
        echo "Unable to update remote IP."
        exit 1
    fi
fi