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How to set and configure standalone Open DHCP Server freeware application ?

Open DHCP server is a free software used to provide IP addresses on your client network. The latest version can be downloaded from

Software installation is very simple, it is done through downloaded installer with a few clicks. You should let installer install server as NT Service. Server configuration is done through OpenDHCPServer.ini file which is located in Open DHCP installation folder.

To configure Open DHCP server, please follow these steps:

(If using Windows ICS) Change IP address of your network card ( to some other IP e.g.
Open Windows Start menu and go to Programs - Open DHCP Server - Configure entry
Important: All configuration entries that have ' character in front of them will not be used
Go to [LISTEN_ON] section and replace default IP address with address of your network card connected to client network
Go to first [RANGE_SET] section
Set DHCP_Range value, this option determines which IP addresses will be leased to client computers, e.g. -
Set Subnet_Mask that will be assigned to clients, it must match DHCP_Range, for example above it would be
Specify primary and secondary DNS_Server which your clients will use to resolve web addresses (it could be DNS server of your ISP or some free like Google DNS,
Router value will be used to set gateway address on client computers, this value have to match IP address of server network card connected to client network

After you configure DHCP server settings, you need to start Open DHCP server service from Control Panel - Administrative Tools - Services application or restart server pc to automatically run DHCP

If program is not assigning addresses, please check:

1. Check network hardware and ensure that client machines has different host names from server and each other.
2. No other service should be running on Server on ports 67.
3. If you get error like port 67 already in use means some other DHCP program or proxy server with DHCP service is running. Use any port scanner program like Active Ports to detect which program is listening on these ports. It is also possible that another copy of DHCPserver itself is running, or Microsoft connection sharing (ICS) is running, which uses these ports.
How to disable ICS DNS/DHCP Service on your target networks, see above INTERNET CONNECTION SHARING.
4. If you still get error Static Interfaces/Listening Ports not available, it may be because of another DHCP Server is running or Interfaces specified on [LISTEN-ON] section are not available.
If your interface may not be ready when your computer/Service starts and due to this service fails to start, use Window's recovery option in Services applet to try starting service at later time.
5. Look at OpenDHCPServer.log (if running as service) or Run in standalone mode, it will provide all debug information as it verbatim the activities.
6. If you use Braodband router, which also has DHCP Server, this program may still run, but some hosts configured by other DHCP Server may not use this DNS or DHCP Service.
Please disable DHCP Service on Broadband Router.
7. DHCPserver.state file backs up current leases and is read back when server restarts. If you want to clean previous leases, you may delete this file and restart the server.
8. If you are not able to receive DHCP Discover messages from clients, make sure that DHCP Server and client are on same physical network (not separated by routers).
If it is separated by routers and it is same subnet, please allow routers to pass broadcast messages to Server on Port 67. If these are different subnets, use the BOOTP relay agent.

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