flush;
spdflush;

spdadd 10.0.1.0/24[any] 10.0.2.0/24[any] any -P out ipsec
        esp/tunnel/172.16.0.1-172.17.0.1/require;

spdadd 10.0.1.0/24[any] 10.0.2.0/24[any] any -P in ipsec
        esp/tunnel/172.17.0.1-172.16.0.1/require;