Issue

• traceroute can not report complete route information when there is no ARP table entry for the gateway. If "traceroute" command is run while the ARP table entry for a gateway is not yet created after the network interface is activated, the reply line from the gateway is missing in the output.

   # traceroute 192.168.100.111
   traceroute to 192.168.100.111 (192.168.100.111), 30 hops max, 40 byte
   packets
   1   (192.168.100.111)  3.156 ms  3.158 ms  3.159 ms
   <This result shows as if the node communicated with 192.168.100.111
   directly.>

• After the ARP entry for the gateway is created, "traceroute" reports complete information as follows.

   # traceroute 192.168.100.111
   traceroute to 192.168.100.111 (192.168.100.111), 30 hops max, 40 byte
   packets
   1   (192.168.10.129)  0.340 ms  0.388 ms  0.498 ms
   2   (192.168.100.111)  1.991 ms  3.582 ms  4.278 ms
   <The result shows 192.168.10.129 is on the path to 192.168.100.111 and
   is relaying the packets.>

• Before and after the creation of the ARP entry for the gateway, there is the difference of behavior. That's found by monitoring tcpdump's ethernet packets. traceroute sends out a probe packet;

   - with TTL = 5 from the first time as follows *before* the creation.
     16:09:21.219427 IP (tos 0x0, ttl   5, id 19641, offset 0, flags [none],
     proto 17, length: 68) 10.186.174.44.60114 > 10.185.132.18.33447: UDP,
     length 40

   - with TTL = 1 at first as follows *after* the creation.
     16:09:31.250217 IP (tos 0x0, ttl   1, id 19645, offset 0, flags [none],
     proto 17, length: 68) 10.186.174.44.46578 > 10.185.132.18.33435: UDP,
     length 40

• Is there something wrong with traceroute package?