38.4. Ipsec VPN

38.4.1. ipsec-tools - IPsec tools for Linux

https://trac.ipsec-tools.net/

38.4.2. openswan - IPSEC utilities for Openswan

http://www.openswan.org/

# yum install openswan

vi /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.send_redirects = 0

ipsec newhostkey --output /etc/ipsec.secert

38.4.3. strongswan - IPSec utilities for strongSwan

http://www.strongswan.org/