How to setup your Computer so that it can always be found on the local area network

DHCP is great for most networking configurations, but in some situations you want the internal IP address to always be the same, rather than dynamically assigned at startup. Here's how.

Apple Menu: System Preferences

Under the Apple Menu select the System Preferences item.

Network Control Panel

Click on the Network control panel

Check out the Settings as assigned by DHCP

The standard approach to working with an ethernet connection or wireless internet setup is to use DHCP (Dynamic Host Configuration Protocol). This works great in most situations, but when we are trying to reliably determine a computer's IP address, it is not reliable enough. Eventually, the host computer will get restarted and be assigned a different IP address. When this happens the router's port forwarding settings get lost.

The solution is to use Manual configuration. First though, take note of the IP Address, Subnet Mask, Router and DNS Server. You will need these when setting up the Manual configuration.

Manual IP Configuration

Then In the Configure Popup, select Manually. Enter the same (Subnet Mask, Router, DNS Server information as before). Enter all the same settings as were obtained from the DHCP configuration. The only difference to enter when setting up the Manual setting will be to select an IP address that is within the range available, but higher than is likely to be selected by any other computer on the network. If you only have a few computers, selecting the extension '.125' is pretty safe. If you are in a big office with lots of computers, you may have to take a higher number. Check with your network administrator for details on this.

Configure your Router

Zoom

Open your Router Configuration screen.

Under the Applications & Gaming tab (on Linksys Routers) Other routers may say something like 'Port Forwarding'. Set your Application port forwarding for FileMaker and VNC, to point at the new address. In this case, it was 192.168.1.125. This is the new manual address for the computer you are seeking to contact from outside the network.

Click Save Settings.