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.
#1: Informational Exchange message must be encrypted
Make sure you have set these parameters in your Sonicwall
IKE (Phase 1) Proposal
DH Group: Group 5 (not 2)
Life Time: 28800
Ipsec (Phase 2) Proposal
Check "Enable Perfect Forward Secrecy"
DH Group: Group 5
Life Time (seconds) 28800
Check these parameters in your linux machine
# vi /etc/ipsec.conf
esp=3DES-SHA1 # protocol used for authentication in sonicwall
Follow the below links for more tutorials
How to configure Samba 4 Secondary Domain Controller
How to secure Apache web server in Linux using password (.htaccess)
How to register Red Hat Linux with RHN (Red Hat Network )
Red hat Enterprise Linux 5.5 Installation Guide (Screenshots)
15 tips to enhance security of your Linux machine
Why is Linux more secure than windows and any other OS
What is the difference between "su" and "su -" in Linux?
What is swappiness and how do we change its value?
How to log iptables messages in different log file
What are the s and k scripts in the etc rcx.d directories
How to check all the currently running services in Linux
How to auto start service after reboot in Linux
What is virtual memory, paging and swap space?