Check external IP address and send a message with Telegram on changes

What This Flow Does

This Node-RED flow periodically checks your external IP address and sends a Telegram message if it changes.

Every 30 minutes:

1. It checks your current external IP address.

2. If the IP is different from the last recorded one, it:

   • Saves the new IP.

   • Sends a Telegram message to notify you.

This is useful if your internet provider gives you a dynamic IP and you want to track when it changes—ideal for home servers or remote access setups. Here's how it works, step by step:

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1. Inject Node: "Check every 30 minutes"

Function: Triggers the flow every 30 minutes.

• Also runs once at startup after a 5-second delay.

• Sends the current timestamp as msg.payload.

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2. HTTP Request: "Get external IP"

Function: Makes a GET request to https://api.ipify.org.

• This service returns your current public (external) IP address in plain text.

• The response becomes the new msg.payload.

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3. Function Node: "Check IP address change"

Function: Compares the new IP address to the previously stored one.

• Retrieves the last known IP from Node-RED's flow memory (flow.get('previousIp')).

• If the new IP is different, it:

  • Stores the new IP (flow.set('previousIp', currentIp)).

  • Sets a message like Nieuw extern IP-adres gedetecteerd: <new IP>.

  • Passes this message along.

• If the IP hasn't changed, it stops (returns null).

// Haal het huidige IP-adres op uit de payload
const currentIp = msg.payload;


// Haal het vorige IP-adres op uit de flow context
const previousIp = flow.get('previousIp') || '';


// Vergelijk het huidige IP met het vorige IP
if (currentIp !== previousIp) {
// Bewaar het nieuwe IP in de flow context
flow.set('previousIp', currentIp);
// Stuur een bericht met het nieuwe IP
msg.payload = 'Nieuw extern IP-adres gedetecteerd: ' + currentIp;
return msg;
} else {
// IP is niet veranderd, stop de flow
return null;
}

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4. Telegram Sender

Function: Sends the notification via your configured Telegram bot if there's a new IP address.

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5. Telegram Bot Configuration

• Connected to a bot named mybot.

• Sends messages to a specified user or chat ID.

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