When using fixed allocation DHCP, there are several factors that are used to determine a computer’s IP address. DHCP (Dynamic Host Configuration Protocol) is a network protocol used to automatically assign IP addresses and other network configuration settings to devices on a network. Fixed allocation DHCP, also known as DHCP reservation, allows network administrators to assign specific IP addresses to certain devices based on their MAC addresses. This ensures that the devices always receive the same IP address whenever they connect to the network.

Here are some of the factors used to determine a computer’s IP address when using fixed allocation DHCP:

1. MAC address: Every network interface card (NIC) has a unique MAC address assigned by the manufacturer. This address is used to identify devices on a network and is used in fixed allocation DHCP to assign specific IP addresses.

2. IP address range: The network administrator defines a range of IP addresses that can be assigned to devices on the network. The fixed allocation DHCP system then allocates addresses from this range based on the MAC address of the requesting device.

3. Device identification: The fixed allocation DHCP system identifies each device by its MAC address when it joins the network. It then checks if a reserved IP address has been assigned to that MAC address and assigns it accordingly.

4. Reservation table: The network administrator maintains a reservation table that associates MAC addresses with specific IP addresses. This table ensures that the same IP address is always assigned to a particular device.

5. Lease time: DHCP also includes a lease time, which determines the duration for which a device can use a specific IP address. When the lease time expires, the device may need to request a new IP address.

6. Network policies: Network administrators can set policies to determine which devices are eligible for fixed allocation DHCP. They can decide which devices receive reserved IP addresses based on specific criteria, such as device type or user privileges.

7. Network topology: The layout and structure of the network can also influence how fixed allocation DHCP assigns IP addresses. The network administrator may need to consider factors such as subnets, VLANs, and other network segmentation techniques.

8. Redundancy and failover: In larger networks, fixed allocation DHCP servers can be redundant and provide failover support. This ensures that IP address assignments continue uninterrupted even if one DHCP server fails.

FAQs:

1. Can I assign multiple IP addresses to a single MAC address?
No, each MAC address can only be associated with a single IP address in fixed allocation DHCP.

2. Can I change the reserved IP address for a device?
Yes, network administrators have the flexibility to change the reserved IP address for a device by modifying the reservation table.

3. What happens if a device’s MAC address changes?
If a device’s MAC address changes, the fixed allocation DHCP system will assign it a new IP address based on the new MAC address.

4. Can I use fixed allocation DHCP for wireless devices?
Yes, fixed allocation DHCP can be used for both wired and wireless devices as long as the MAC address of the device is known.

5. Can I reserve IP addresses for devices that are not currently connected to the network?
Yes, network administrators can reserve IP addresses for devices that are not currently connected, ensuring they receive the same IP address when they connect in the future.

6. How can I view the reservation table?
The reservation table can be viewed and modified through the DHCP server’s management interface or configuration file.

7. Can I have dynamic IP addresses alongside fixed allocation DHCP?
Yes, it is possible to have a combination of fixed allocation DHCP and dynamic IP address assignments on the same network.

8. Can I reserve IP addresses for devices based on their hostname?
In some DHCP server implementations, it is possible to reserve IP addresses based on device hostnames, in addition to MAC addresses.