How to Fix "Informational Exchange message must be encrypted"

This is the error you might get while configuring Openswan. As I received this error when I was configuring openswan to connect my sonicwall vpn.

Error:

#1: Informational Exchange message must be encrypted  

Solution:

Make sure you have set these parameters in your Sonicwall 

IKE (Phase 1) Proposal  
DH Group: Group 5 (not 2)  
Encryption: 3DES  
Authentication: SHA1  
Life Time: 28800

Ipsec (Phase 2) Proposal  
Protocol: ESP  
Encryption: 3DES  
Authentication: SHA1  

Check "Enable Perfect Forward Secrecy"

DH Group: Group 5  
Life Time (seconds) 28800   

Check these parameters in your linux machine

# vi /etc/ipsec.conf  
       auth=esp  
       esp=3DES-SHA1            # protocol used for authentication in sonicwall  
       ike=3DES-SHA1

To view a screenshot of this page on sonicwall click on the following link

Sonicwall configuration for VPN

To have a look at all the configuration files and steps follow this page:

openswan configuration in Red Hat linux

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