FreeBSD - 1
# flush previous SAD & SPD
flush;
spdflush;

# Security Association Database
# For ESP
add 10.15.15.1 10.15.15.2 esp 1011 -E 3des-cbc "myveryverysecretpassphrase";
add 10.15.15.2 10.15.15.1 esp 1012 -E 3des-cbc "myveryverysecretpassphrase";

# For AH
add 10.15.15.1 10.15.15.2 ah 1234 -A hmac-md5 "verysecrettoo";
add 10.15.15.2 10.15.15.1 ah 1235 -A hmac-md5 "verysecrettoo";

# Security Policy Database
spdadd 10.15.15.2/32 10.15.15.1/32 any -P in ipsec esp/tunnel/10.15.15.2-10.15.15.1/require
ah/tunnel/10.15.15.2-10.15.15.1/use;

spdadd 10.15.15.1/32 10.15.15.2/32 any -P out ipsec esp/tunnel/10.15.15.1-10.15.15.2/require
ah/tunnel/10.15.15.1-10.15.15.2/use;

FreeBSD - 2
# flush previous SAD & SPD
flush;
spdflush;

# Security Association Database
# For ESP
add 10.15.15.1 10.15.15.2 esp 1011 -E 3des-cbc "myveryverysecretpassphrase";
add 10.15.15.2 10.15.15.1 esp 1012 -E 3des-cbc "myveryverysecretpassphrase";

# For AH
add 10.15.15.1 10.15.15.2 ah 1234 -A hmac-md5 "verysecrettoo";
add 10.15.15.2 10.15.15.1 ah 1235 -A hmac-md5 "verysecrettoo";

# Security Policy Database
spdadd 10.15.15.2/32 10.15.15.1/32 any -P out ipsec esp/tunnel/10.15.15.2-10.15.15.1/require
ah/tunnel/10.15.15.2-10.15.15.1/use;

spdadd 10.15.15.1/32 10.15.15.2/32 any -P in ipsec esp/tunnel/10.15.15.1-10.15.15.2/require
ah/tunnel/10.15.15.1-10.15.15.2/use;