TP-Link WiFi Router LAN and DHCP Setting for better stability

Properly configuring the LAN and the DHCP server setting is necessary for the stability of the network created by the Tplink router operating in router mode .

LAN Settings

The LAN setting is located in Advanced > Network > LAN.

For your TP-Link WiFi router, the LAN IP address and subnet mask are key settings that control how the router operates within your local network. Below is everything you need to know about these settings.

What Are LAN IP Address and Subnet Mask?

  • LAN IP Address: This is the unique identifier for your router on your local network. It’s the address you type into a web browser to access the router’s configuration page and the gateway that devices use to communicate through the router.
    • Function:
      • It serves as the gateway for your local network.
      • Devices on your network send traffic to this IP address to reach other devices on the LAN or the internet.  
  • Subnet Mask: This defines the range of IP addresses available for devices on your network. It determines how many devices can connect by separating the network portion of the IP address from the device-specific portion.

Default Settings

Most TP-Link WiFi routers come with the following default values:

  • LAN IP Address: Either 192.168.0.1 or 192.168.1.1 (varies by model).
  • Subnet Mask: 255.255.255.0.

With a subnet mask of 255.255.255.0, your network can support up to 254 devices (e.g., IP addresses from 192.168.0.2 to 192.168.0.254 if the router is 192.168.0.1).

Why These Settings Matter

  • The LAN IP address must be unique to avoid conflicts with other devices or networks (e.g., a modem or another router).
  • The subnet mask ensures all devices are within the same address range, enabling proper communication.
  • If your router connects to another network, these settings must be configured to prevent overlapping IP ranges.

Things to Watch Out For

  • Avoid Conflicts: Ensure the new IP address doesn’t overlap with other devices or networks.
    • For example, if your modem uses 192.168.0.x, set your router to 192.168.10.1 or a different range like 192.168.20.1,192.168.35.1.
    • For example, if there are multiple routers in a network then the IP address of each router must be different from each other.
      • IP address of Router_1 is 192.168.10.1 then,
      • The IP address of Router_2 is 192.168.20.1
      • The IP address of Router_3 is 192.168.40.1
      • The IP address of Router_4 is 192.168.42.1
  • DHCP Adjustments: Changing the LAN IP address updates the router’s DHCP range (which assigns IPs to devices) automatically. However, static IPs or port forwarding rules may need manual updates.

Configuring the LAN IP address setting other than default settings will help in stabilizing the the local area network.

LAN IP Address Example:

  • 192.168.10.1
  • 192.168.11.1
  • 192.168.12.1
  • 192.168.20.1
  • 192.168.30.1
  • 192.168.40.1
  • 192.168.41.1
  • 192.168.42.1
  • 192.168.45.1

Example_1

Example 2

DHCP Server Setting

For reference we will use Router IP Address: 192.168.35.1 and Subnet mask: 255.255.255.0

IP Address Pool

  • What it is: The IP Address Pool is the range of IP addresses that the DHCP server assigns to devices connecting to your network. It must fall within the router’s LAN subnet. For example, if your router’s IP is 192.168.35.1 with a subnet mask of 255.255.255.0, valid addresses range from 192.168.35.2 to 192.168.35.254.
  • How it works:
    • When a device (like a smartphone or laptop) connects to your Wi-Fi network, it requests an IP address.
    • The router’s DHCP server then assigns an available IP address from the defined pool.
    • This automates the process of IP address assignment, so you don’t have to manually configure each device.
  • How to configure it:
    • Set a range that suits your network’s size while reserving space for devices with static IPs (e.g., printers or servers). A common setting for home networks is 192.168.35.100 to 192.168.35.199, which supports up to 100 devices.
    • If you expect more devices, expand it (e.g., 192.168.35.50 to 192.168.35.200). For fewer devices, a smaller range like 192.168.35.100 to 192.168.35.150 works.
    • Tip: Avoid overlap with static IPs. For instance, reserve 192.168.35.2 to 192.168.35.99 for manual assignments and use 192.168.35.100 onward for the DHCP pool.

Address Lease Time

  • What it is: This determines how long a device keeps its assigned IP address before it must renew it with the DHCP server. Once the lease expires, the device requests a new IP (though it often retains the same one).
  • How it works:
    • When a device receives an IP address, it’s granted that address for the specified lease time.  
    • Before the lease expires, the device typically requests to renew the lease, which the router can grant or deny.  
    • If the lease expires and the device hasn’t renewed, the IP address becomes available for reassignment.  
  • How to configure it:
    • For a typical home network, set it to 1440 minutes (24 hours). This provides a good balance between stability and flexibility.
    • For networks with many temporary devices (e.g., guests), a shorter lease like 120 minutes (2 hours) frees up IPs faster.
    • For very stable networks, a longer lease like 2880 minutes (48 hours) reduces renewals, but 24 hours is usually sufficient.
    • Tip: For devices needing a consistent IP (e.g., a media server), use DHCP reservation (available in most TP-Link routers) instead of relying on long lease times.

Default Gateway

  • What it is: The Default Gateway is the IP address of your router. It serves as the central point that routes traffic between your local network (LAN) and the internet. Devices on your network send their internet-bound traffic to this address.
  • Devices connecting to the router will be assigned the default gateway as mentioned here.

Primary DNS

  • What it is: DNS (Domain Name System) translates domain names (e.g., www.google.com) into IP addresses that devices understand. The Primary DNS is the first server your devices query for this translation.
  • How to set it: For simplicity, set this to your router’s IP address (e.g., 192.168.35.1). This allows the router to manage DNS requests and forward them to your ISP’s DNS servers or any custom DNS servers you’ve set in the router.
  • Alternative option: You can use an external DNS server like Google’s (8.8.8.8) or Cloudflare’s (1.1.1.1) for potentially faster or more private DNS resolution. However, using the router’s IP is usually sufficient for most home users.

Secondary DNS

  • What it is: The Secondary DNS acts as a backup if the Primary DNS server is unavailable. It ensures your devices can still resolve domain names even if the primary server fails.
  • How to set it: This is optional, but for added reliability, you can set it to an external DNS server like Google’s (8.8.4.4). Alternatively, you can leave it blank.
  • Why it’s useful: A secondary DNS improves network reliability, especially during outages of the primary DNS server.

Example 1

If the LAN setting is:

  • IP Address: 192.168.35.1
  • Subnet Mask: 255.255.255.0

Then DHCP Server settings should be:

  • IP address pool available: 192.168.35.2 to 192.168.35.254
  • Assigned IP address pool: 192.168.35.10 to 192.168.35.250
  • Address Lease Time: 1440
  • Default Gateway: 192.168.35.1
  • Primary DNS: 192.168.35.1
  • Secondary DNS: 192.168.35.1

Example 2

If the LAN setting is:

  • IP Address: 192.168.50.1
  • Subnet Mask: 255.255.255.0

Then DHCP Server settings should be:

  • IP address pool available: 192.168.50.2 to 192.168.50.254
  • Assigned IP address pool: 192.168.35.100 to 192.168.35.199
  • Address Lease Time: 1440
  • Default Gateway: 192.168.50.1
  • Primary DNS: 8.8.8.8
  • Secondary DNS: 1.1.1.1