Manual and Automatic Addressing

On a home network, the router typically determines how the LAN should function. The router will transport traffic between LAN clients as well as between the LAN and the Internet. The router in the network distributes IP addresses and other network-related information to the PCs. This was accomplished through the use of DHCP, which stands for Dynamic Host Configuration Protocol. In other terms, it is a protocol for automatically distributing configuration to PCs and other network devices.

• When you buy a home router, it is usually pre-configured with a DHCP server to distribute configuration to your PCs and other devices. The router is also configured so that the DHCP addresses it distributes are on the same IP network as the router’s LAN IP address. This is required so that the clients can utilize the router as their Default Gateway.
• When a computer joins a network, it attempts to obtain an IP address. This was accomplished by sending out a DHCP request that inquires about the availability of DHCP servers on the network. If a DHCP server answers, the machine will use DHCP to request an IP address and any other information it needs from the DHCP server. When your router receives this DHCP request, it will assign an available IP address from its pool of free IP addresses, along with the other information that the computer requires.

Manual Configuration of IP Addresses:

Instead of allowing the computer to acquire its IP address from the network via DHCP, you can specify the IP settings on the computer manually. Normally, this is discouraged since it can cause a variety of issues if not managed properly by the administrator.

Need to Configure the IP Address Manually:

If a computer acquires its IP address automatically through DHCP, it is not guaranteed that the computer will obtain the same IP address each time it is started. The DHCP server remembers which computer received which IP address, but only for a limited time. If a computer is turned off for an extended period of time (typically a day or two, depending on how the network is set up), the DHCP server will forget whatever IP address it assigned to the computer. Furthermore, if the router is turned down for whatever reason, it will often forget about any DHCP leases it has previously issued.

In rare cases, this can cause problems. For example, you may need to do port forwarding. Port forwarding typically refers to a computer’s internal LAN IP address. Port forwarding works as long as the PC keeps the same IP address. However, if your computer’s IP address changes frequently, you may need to adjust port forwarding in your router settings each time the IP address changes. In this case, normally manually configuring the computer to receive port forwarding using its IP address should be preferred. This way the IP address will always stay the same and port forwarding will still work.

The same configurations that a computer ordinarily receives via DHCP must be made when configuring an IP address manually on a computer:

• A working IP address on the router’s same IP network
• Default Gateway should be set to the router’s LAN IP address DNS Server address, which can either be the router’s LAN IP address or another DNS server on the Internet. 
• The same Subnet Mask that the router is using should be used. 
• You can utilize identical addresses that the router typically distributes via DHCP.

IP Address Conflicts:

Make sure to remove the IP address from the pool of DHCP addresses in your home network if you decide to manually establish an IP address on a PC. If not, the router can assign the same IP address to another network device. On a computer network, if two devices were set to share the exact same IP address, it leads to an IP address dispute on the network, which essentially prevents communication for the clients concerned. If just around half of the traffic arrives at the intended destination, network connectivity will not function. The computers will attempt to prevent IP address conflicts in more recent operating systems and contemporary networks by first determining if the IP address appears to be taken. However, only the initial machine to receive an IP address will function properly. When a second computer receives the same IP address as the first one inadvertently, it will become aware of the conflict and stop communicating on the network until a different IP address is assigned to it.

Parameter	Automatic Addressing	Manual Addressing
Definition	Automatic addressing implies the automatic assignment of IP addresses to the device on the network.	Manual address implies a manual assignment of IP addresses for the device on the network.
Responsible	DHCP is responsible for automatic addressing.	The Administrator (User) is responsible for manual addressing.
Conflicts	There are no such conflicts in automatic addressing.	For manual addressing, IP address conflicts can arise if you forget to remove the IP address from the pool of DHCP addresses in your home network.
User involvement	It does not require user involvement.	It requires user involvement throughout the whole process.
Updation	It is not necessary that the computer will obtain the same IP address each time it is started.	The address remains the same as it is static.