Avoiding Repetitive IP Address Allocation
Understanding a protocol helps us quickly find any failure in the network, then we can understand how the DHCP server avoids the repeated assignment of an IP address.
Before assigning an IP address to a client, the DHCP server needs to ping the IP address to avoid address conflicts.
By using the ping command, you can check whether there is a response to the ping packet within the specific time. If no response to the ping packet is received, the DHCP server keeps sending ping packets to the IP address to be assigned until the number of the sent ping packets reaches the maximum value. If there is still no response, it indicates that the IP address is not in use and can be allocated to the client. This ensures that the IP address assigned to the client is unique (This is implemented based on RFC 2132.)
By default, up to two ping packets can be sent and the longest time to wait for a response is 500 ms.
As we can see, the TCP / IP protocols are interrelated in this case using the ping of the ICMP protocol.
