I’m looking for a plugin or a setting which can add a warning page before redirecting to an external link in any topic, of-course on a self hosted discourse instance. The intention is to prevent phishing attacks.

You can rewrite external links using a theme-component as described by Redirect Page for External URLs - #14 by Johani

אזהרה לפני קישור חיצוני

Falco (Falco) 10 בפברואר,‏ 2021,‏ 1:44pm 6

לייק 1

נושא		תגובות	צפיות
Preventing malicious linking Feature	35	4787	26 בדצמבר,‏ 2017
Redirect Page for External URLs Support	15	3044	31 במרץ,‏ 2022
External Link Shield – Exit Confirmation & Trust Gating Theme component	4	132	14 בינואר,‏ 2026
Link warning outside of forums Feature	4	1001	9 בנובמבר,‏ 2017
Plugin to rewrite external links on new posts Marketplace	4	664	17 במאי,‏ 2018