Include the saved output in your lab report and interpret the results. How many of the Linux PCs responded to the broadcast ping?
What will be an ideal response?
```
[root@host1 /root]# ping -c 1 111.111.111.111
connect: Network is unreachable
[root@host1 /root]# ping -c 1 -b 10.0.1.255
WARNING: pinging broadcast address
PING 10.0.1.255 (10.0.1.255) from 10.0.1.11 56(84) bytes of data.
64 bytes from 10.0.1.11: icmp_seq=1 ttl=644 time=15.464 ms
--- 10.0.1.255 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
rtt min/avg/max/mdev = 15.464/15.464/15.464/0.000 ms
```
When PC1 issues a PING to the address 111.111.111.111, it tries to obtain the IP address of the next- hop router to reach the network including 111.111.111.111. This is because there is no match in the route table entries and there is not a default route configured in PC1. Therefore, tcpdump cannot capture any packets in this case.
```
WARNING: pinging broadcast address
PING 10.0.1.255 (10.0.1.255) from 10.0.1.11 : 56(84) bytes of data.
64 bytes from 10.0.1.11: icmp_seq=1 ttl=255 time=1.332 ms
11
64 bytes from 10.0.1.13: icmp_seq=1 ttl=255 time=1.496 ms (DUP!)
64 bytes from 10.0.1.12: icmp_seq=1 ttl=255 time=1.590 ms (DUP!)
64 bytes from 10.0.1.14: icmp_seq=1 ttl=255 time=1.678 ms (DUP!)
64 bytes from 10.0.1.11: icmp_seq=2 ttl=255 time=0.817 ms
--- 10.0.1.255 ping statistics ---
2 packets transmitted, 2 received, +3 duplicates, 0% packet loss, time 1520ms
rtt min/avg/max/mdev = 0.817/1.382/1.678/0.307 ms
```
Tcpdump Data:
```
19:55:32.500000 10.0.1.11 > 10.0.1.255: icmp: echo request (DF)
19:55:32.500000 10.0.1.11 > 10.0.1.11: icmp: echo reply (DF)
19:55:32.500000 10.0.1.11 > 10.0.1.11: icmp: echo reply (DF)
19:55:32.500000 10.0.1.13 > 10.0.1.11: icmp: echo reply (DF)
19:55:32.500000 10.0.1.12 > 10.0.1.11: icmp: echo reply (DF)
19:55:32.500000 10.0.1.14 > 10.0.1.11: icmp: echo reply (DF)
19:55:33.500000 10.0.1.11 > 10.0.1.255: icmp: echo request (DF)
19:55:33.500000 10.0.1.11 > 10.0.1.11: icmp: echo reply (DF)
19:55:33.500000 10.0.1.11 > 10.0.1.11: icmp: echo reply (DF)
19:55:33.500000 10.0.1.13 > 10.0.1.11: icmp: echo reply (DF)
19:55:33.500000 10.0.1.14 > 10.0.1.11: icmp: echo reply (DF)
19:55:33.500000 10.0.1.12 > 10.0.1.11: icmp: echo reply (DF)
```
The broadcast is an address with the host portion set to all 1’s and is used when messages have to be sent
to all the hosts on a network. For our network 10.0.1.255 is the broadcast address, thus when PC1 issues a
ping 10.0.1.255, the request is broadcast to all local networks and the replies are received from hosts in
the same network segment. If the packet is to reach host’s own IP address, it can be copied to the loopback interface rather than sending out the packets if the packets destination is its own IP, or send the packets through the cable. In this case, four hosts 10.0.1.11, 10.0.1.13, 10.0.1.12, 10.0.1.14 replied to the ping issued by PC1.