Describe which of the ping commands are successful and which fail. Use the data that you captured to determine the route of the ICMP Echo Request and Reply packets. For each route, provide an explanation why the path is taken for each for the ping commands.

What will be an ideal response?

1. PC1 pings PC3:
```
[root@PC1 root]# ping -c 1 10.0.4.31
PING 10.0.4.31 (10.0.4.31) 56(84) bytes of data.
64 bytes from 10.0.4.31: icmp_seq=1 ttl=62 time=7.61 ms
--- 10.0.4.31 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 7.611/7.611/7.611/0.000 ms
```
We notice that the ping command was successful.
The path taken by the ping request to reach PC3 can be shown as :
PC1 (sends ping request to default gateway R2, determined by destn MAC address) ? R1 (switch) ? R2
(sends request to default gateway R3) ? R3 (Send the request to subnet 10.0.4.0) ? R4 (Switch) ? PC3
The ICMP reply from PC3 would follow the reverse of the above path.
2. PC1 pings PC4:
```
[root@PC1 root]# ping -c 1 10.0.4.41
PING 10.0.4.41 (10.0.4.41) 56(84) bytes of data.
--- 10.0.4.41 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms
```
3. PC4 pings PC1:
```
[root@PC4 root]# ping -c 1 10.0.1.11
PING 10.0.1.11 (10.0.1.11) 56(84) bytes of data.
64 bytes from 10.0.1.11: icmp_seq=1 ttl=62 time=1.63 ms
--- 10.0.1.11 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.635/1.635/1.635/0.000 ms
```
The ping command was a success. This will be successful only if Proxy ARP is enabled on the host and
the routers
PC4 (Ping Request) ? R3 (Send the request to subnet 10.0.3.0) ? R2 (Send the request to
subnet 10.0.1.0) ? R1 (Switch) ? PC1
The reply from PC1 would follow the reverse of the above path.
4. PC1 pings PC2:
```
[root@PC1 root]# ping -c 1 10.0.3.21
PING 10.0.3.21 (10.0.3.21) 56(84) bytes of data.
64 bytes from 10.0.3.21: icmp_seq=1 ttl=63 time=1.52 ms
--- 10.0.3.21 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.524/1.524/1.524/0.000 ms
```
The ping command is successful.
The path taken by the echo ping request is:
PC1 (Ping Request) ? R1 (Switch) ? R2 (Send the request to subnet 10.0.3.0) ? PC2
The reply from PC2 follows the reverse path.