Chapter 26 L2TP VPN Example
Figure 254 Connect L2TP to ZyWALL: Security
11 Select Optional encryption (connect even if no encryption) and the Allow these protocols radio button. Select Unencrypted password (PAP) and clear all of the other check boxes. Click OK.
Figure 255 Connect ZyWALL L2TP: Security > Advanced
12 Click IPSec Settings.