IP Security Protocol (ipsec) allows us to define rules regarding the travel of packets on a network. Often Ipsec is used for crafting VPN tunnels. Here are some commands a network administrator would find handy when setting up or modifying a VPN structure.
#kill isakmpd which is responsible for encrypted/authenticated network traffic aka the VPN tunnels pkill isakmpd #start the isakmpd daemon isakmpd -T -K #load the ipsec configuration file using ipsec ipsecctl -f /etc/ipsec.conf # use the -n option to specify only to load ipsec rules if there are no errors ipsecctl -n -f /etc/ipsec.conf #check the ipsec flows and SAs. SAs are essentially the VPN tunnel ipsecctl -s all