On Router 1, issue a ping command to the lo0 interface on Router 4 to send traffic across the IPSec tunnel.
user@R1> ping 10.0.0.4
PING 10.0.0.4 (10.0.0.4): 56 data bytes 64 bytes from 10.0.0.4: icmp_seq=0 ttl=254 time=1.375 ms 64 bytes from 10.0.0.4: icmp_seq=1 ttl=254 time=18.375 ms 64 bytes from 10.0.0.4: icmp_seq=2 ttl=254 time=1.120 ms ^C --- 10.0.0.4 ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max/stddev = 1.120/6.957/18.375/8.075 ms