docs(addons): remove vpn ipsec addon page

redirections.yml

@@ -873,6 +873,12 @@
   - old: "/platform/deployment/unknown-technology"
     new: "/platform/app/troubleshooting/deployment-issues#unknown-technology"
 
+  - old: "/addons/scalingo-vpn-ipsec"
+    new: "/changelog#changelog-addons-2026-05-18-scalingo-vpn-ipsec-deprecated"
+
+  - old: "/addons/scalingo-vpn-ipsec/start"
+    new: "/changelog#changelog-addons-2026-05-18-scalingo-vpn-ipsec-deprecated"
+
 obsolete:
   - "/how-to-migrate-from-cloudcontrol/"
   - "/how-to-migrate-from-shelly-cloud/"

src/_posts/security/overview/2000-01-01-connectivity.md

@@ -14,6 +14,6 @@ from the latest security vulnerabilities.
 
 ### Customer VPN
 
-We offer the possibility to set up a VPN connection (OpenVPN, IPSec) between your infrastructure and the Scalingo
+We offer the possibility to set up a VPN connection (OpenVPN) between your infrastructure and the Scalingo
 platform. This allows you to securely connect your infrastructure to the platform and to protect your data from
 unauthorized access.

src/changelog/addons/_posts/2026-05-18-scalingo-vpn-ipsec-deprecated.md

@@ -0,0 +1,10 @@
+---
+modified_at: 2026-05-18 00:00:00
+title: 'Scalingo VPNC IPSec Addon has been removed'
+---
+
+The Scalingo VPNC IPSec addon has been removed and can no longer be used. It
+was based on the legacy `vpnc` technology and IKEv1, which is deprecated.
+
+For VPN connectivity from application containers, use the
+[Scalingo OpenVPN addon]({% post_url addons/scalingo-openvpn/2000-01-01-start %}).