Warn Users When Links Redirect Outside of Salesforce
Where: This feature is available in Salesforce Classic in all editions.
Why: For instance, users see a warning message if they click a link to a company’s website on an account record.
This setting applies to all links in Salesforce, except for links in Chatter.
How: In Setup, search for Session Settings. Under Redirections, select Warn users before they are redirected outside of Salesforce.