In Salesforce IP whitelisting is one of the most effective methods of ensuring secure connections to external systems. Salesforce provides a range of IP addresses that can be whitelisted by external systems based on your Salesforce instance.

Note: Add https://api.ipify.org in your Org remote site settings before executing below code.

Sample Code:

HttpRequest request = new HttpRequest();
request.setEndpoint('https://api.ipify.org');
request.setMethod('GET');
Http http = new Http();
HttpResponse response = http.send(req);
String responseBody = response.getBody();
System.debug('Your Org current IP Address: ' + responseBody);