Cloudflare DynDNS Script for Synology NAS

cloudflare-synology-dyndns.sh

### Cloudflare Dynamic DNS for Synology NAS
# 1. Open Synology Task Manager (Synology UI -> Control Panel -> Task Scheduler)
# 2. Create task, define schedule, notification, etc
# 5. Define this Bash Script and specify your zone, dnsrecord to updatte, and Cloudflare API Token (https://dash.cloudflare.com/profile/api-tokens)

#!/bin/bash
# Settings
zone=example.com
dnsrecord=abc.example.com
cloudflare_auth_token=12345678910QAZXSWEDCVFRTGB1234567890asdw

# Get the current external IP address
ip=$(curl -s -X GET https://checkip.amazonaws.com)

echo "Current IP is $ip"

if nslookup $dnsrecord 1.0.0.1 | awk -F': ' 'NR==6 { print $2 } ' | grep "$ip"; then
  echo "$dnsrecord is currently set to $ip; no changes needed"
  exit
fi

# Get the zone ID for the requested zone
zoneid=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone&status=active" \
  -H "Authorization: Bearer ${cloudflare_auth_token}" \
  -H "Content-Type: application/json" | grep -o '"id":"[^"]*' | grep -o '[^"]*$' | head -n 1)

echo "Zone ID for $zone is $zoneid"

# Get the DNS record ID
dnsrecordid=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zoneid/dns_records?type=A&name=$dnsrecord" \
  -H "Authorization: Bearer ${cloudflare_auth_token}" \
  -H "Content-Type: application/json" | grep -o '"id":"[^"]*' | grep -o '[^"]*$')

echo "DNS record ID for $dnsrecord is $dnsrecordid"

# Update the record
curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zoneid/dns_records/$dnsrecordid" \
  -H "Authorization: Bearer ${cloudflare_auth_token}" \
  -H "Content-Type: application/json" \
  --data "{\"type\":\"A\",\"name\":\"$dnsrecord\",\"content\":\"$ip\",\"ttl\":1,\"proxied\":false}"