said by JimE:You can't ping the modem from behind the router/switch.
Since when? Most home routers allow it, since they don't block RFC1918 addresses from crossing the WAN link:
$ ping 192.168.100.1
PING 192.168.100.1 (192.168.100.1): 56 data bytes
64 bytes from 192.168.100.1: icmp_seq=0 ttl=63 time=2.903 ms
64 bytes from 192.168.100.1: icmp_seq=1 ttl=63 time=2.480 ms
64 bytes from 192.168.100.1: icmp_seq=2 ttl=63 time=2.472 ms
64 bytes from 192.168.100.1: icmp_seq=3 ttl=63 time=2.482 ms
64 bytes from 192.168.100.1: icmp_seq=4 ttl=63 time=2.510 ms
^C
--- 192.168.100.1 ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 2.472/2.569/2.903/0.167 ms
$ traceroute 192.168.100.1
traceroute to 192.168.100.1 (192.168.100.1), 64 hops max, 52 byte packets
1 home-router (192.168.1.1) 0.975 ms 0.676 ms 0.604 ms
2 192.168.100.1 (192.168.100.1) 2.476 ms 2.496 ms 2.416 ms
$