What are the settings for configuring L2TP VPN on macOS 15 (Sequoia) using old USG/ZyWALL series?

Zyxel_Emily

Question:
What are the settings for configuring L2TP/IPSec VPN on macOS 15 (Sequoia) using old USG/ZyWALL series?

Answer:
To configure L2TP VPN for macOS 15 (Sequoia) with the Zyxel USG40 and other USG/ZyWALL using firmware 4.73 patch 2, please follow these settings based on the successful configurations:

Phase 1 (Gateway)
Encryption Algorithm: 3DES
Authentication Algorithm: SHA1
Key Exchange: DH2

Phase 2 (Connection)
Encryption Algorithm: 3DES
Authentication Algorithm: SHA1
Perfect Forward Secrecy (PFS): None

With these settings, your macOS 15 should connect successfully using the native VPN client.