I'd like to start this section by recapping what we already know about DHCP. You should recall that DHCP is used to issue an IP address automatically to any host that requests it. To do this, the process of DORA is followed:
- Discover: The client sends a broadcast packet to discover the DHCP server.
- Offer: The DHCP server offers an IP address and other information to the host.
- Request: The client, on receipt of the offer, requests the IP address and other details provided by the server.
- Acknowledge: The server sends an acknowledgement that the IP address has been issued to that client.
Figure 14.1 shows a Wireshark capture of the DHCP process. Note that on the first line, the source IP address is 0.0.0.0, as the requesting device does not have an IP address as of yet; and the destination address is the general broadcast address of 255.255.255.255. On the second line...
