Setup DHCP Server

Content:
Description of the DHCP Server
Teltonika Router
    - Set IP address pool of the DHCP Server
    - Add Static Lease
Advantech Router
    - Set IP address pool of the DHCP Server
    - Add Static Lease
 

Description of the DHCP Server

A DHCP Server assigns an IP address to connected devices that are connected via LAN or WLAN of the router. The devices automatically receive an IP address from an IP address range defined in the router.

If several devices are connected according to Why do not all devices connected to the router get internet access? and do not receive an IP address, the DHCP address pool is probably exhausted, which prevents access to the router and the internet. 

The DHCP server of the router can be extended. However, it must first be clarified how the router is used. 

• Is it a pure "Internet router", i.e. should the connected devices only access the internet? Then the DHCP IP address range can be easily extended. 

• If the connected devices should also be accessible from outside, it must be ensured that the connected devices always receive the same IP address on which the port forwarding is set up. 

  According to Set up Static Lease, a fixed link must then be established. 
  Alternatively, we recommend configuring fixed IP addresses in the connected devices when connecting multiple devices, instead of obtaining them automatically from the DHCP server. This simplifies management, especially when replacing an device, as the existing link does not have to be deleted and a new link with the new MAC address set up.  

Teltonika Router

Set IP address pool of the DHCP Server

1. Log into the WebUI of the Teltonika router. 
2. You can check and edit the settings of the DHCP server under Network -> DHCP -> Server Settings . (In older firmware versions under Network -> LAN).
3. By selecting 'Edit' you get to the settings where you can define the DHCP range. 
   
   
    
4. Here you can adjust or extend the IP range of the DHCP server for devices connected via LAN or WLAN. 
   • Start IP address: First IP address assigned by the DHCP server.
   • End IP address: Last IP address assigned by the DHCP server.

   • Leasetime: After the leasetime expires, the IP address is released. If the device remains connected, it automatically renews the IP to maintain the connection.

     

     Further information can be found on the official Teltonika website, for example at https://wiki.teltonika-networks.com/view/RUT956_DHCP#DHCP_server_configuration.
      

5. If you have set up port forwarding for specific connected devices, continue with Set up Static Lease.

Add Static Lease

The DHCP Static Lease (IP reservation) is a method to permanently assign a fixed IP address from the DHCP server to a specific device within a network, although IP addresses are usually assigned dynamically via DHCP. This is done by permanently linking an IP address to the MAC address of the device. Thus, the device always receives the same IP from the DHCP server without manual settings. This is particularly necessary if port forwarding to specific IP addresses has been set up in the router. 

Under Status -> Network -> LAN in the section DHCP Leases, you can see the devices that have already obtained an IP address from the DHCP server. By clicking "Create Static" this link can be permanently set. 

Under Network -> DHCP -> Static Leases the corresponding links of devices to specific IP addresses can be manually made, adjusted or already established links deleted again: 

• MAC: MAC address of the device.
• IP: IP address that the DHCP server should assign.
• Hostname: Device name

Further information can be found on the official Teltonika website, for example at https://wiki.teltonika-networks.com/view/RUT956_DHCP#Static_Leases.

Advantech Router

Set IP address pool of the DHCP Server

1. Log in to the router's web interface.

2. The DHCP server settings can be reviewed and modified under Configuration -> LAN.

   

   • IP Pool Start: The first IP address assigned by the DHCP server.
   • IP Pool End: The last IP address allocated by the DHCP server.
   • Lease Time: Upon expiry of the lease time, the IP address is released. If the device remains connected, it will automatically renew the IP address to maintain the connection.

Add Static Lease

The DHCP Static Lease (IP reservation) is a method to permanently assign a fixed IP address from the DHCP server to a specific device within a network, although IP addresses are usually assigned dynamically via DHCP. This is done by permanently linking an IP address to the MAC address of the device. Thus, the device always receives the same IP from the DHCP server without manual settings. This is particularly necessary if port forwarding to specific IP addresses has been set up in the router. 

Under Configuration -> LAN, the option 'Enable dynamic DHCP leases' must be enabled. Here, the MAC addresses of the client devices as well as the desired IP addresses to be assigned to these devices can be entered.