# setfib 1 route add default 10.0.0.1
add net default: gateway 10.0.0.1 fib 1

# setfib 1 ping 10.0.0.1
PING 10.0.0.1 (10.0.0.1): 56 data bytes
64 bytes from 10.0.0.1: icmp_seq=0 ttl=64 time=0.043 ms
^C
--- 10.0.0.1 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.043/0.043/0.043/0.000 ms

# setfib 1 ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
36 bytes from this_server.my.domain (10.0.0.1): Time to live exceeded
Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst
 4  5  00 0054 24ce   0 0000  01  01 3f00 10.0.0.1  8.8.8.8

^C
--- 8.8.8.8 ping statistics ---
1 packets transmitted, 0 packets received, 100.0% packet loss

# setfib 1 traceroute 8.8.8.8
traceroute to 8.8.8.8 (8.8.8.8), 64 hops max, 40 byte packets
 1  this_server (10.0.0.1)  0.043 ms  0.036 ms  0.024 ms
 2  this_server (10.0.0.1)  0.033 ms  0.030 ms  0.028 ms
 3  this_server (10.0.0.1)  0.027 ms  0.031 ms  0.032 ms
    ...snip...
64  this_server (10.0.0.1)  0.132 ms  0.138 ms  0.137 ms

# netstat -r4
Routing tables

Internet:
Destination        Gateway            Flags     Netif Expire
default            lo0-100.NYCMNY-VFT UGS         em0
10.0.0.0/16        link#1             U           re0

# setfib 1 netstat -r4
Routing tables (fib: 1)

Internet:
Destination        Gateway            Flags     Netif Expire
default            this_server        UGS         re0
10.0.0.0/16        link#1             U           re0

setfib 1 route add default <router on 10.0.0.0 network>