How to set a static IP address on Windows 11

To reach a ZGW-20 over a direct Ethernet cable, the laptop needs a fixed address on the Gateway's management subnet, 172.31.255.0/24. The management port does not give out addresses, so a laptop left on automatic addressing cannot reach it.

EpiSensor direct-management settings

A ZGW-20 with factory network settings answers at 172.31.255.1/24 on its management port. On the connector side this is the port labelled 1Gb ETH. The 2.5Gb ETH port is the uplink to the site network. The management port does not supply a default route or DNS.

These values are not a universal EpiSensor default. A Gateway that was upgraded from an older image, or whose network settings were changed on site, can use different addresses. If you can already reach Edge on the site network, open Settings > Networking. The profile named ZGW20 Management Ethernet lists the management address. When this port is on a network with a DHCP server, it can also have a second, DHCP-assigned address. The 172.31.255.1 address stays in place.

This procedure changes the laptop, not the Gateway.

Before changing the address

1. Open Command Prompt.
2. Run ipconfig /all > "%USERPROFILE%\ipconfig-before.txt". This file records the original address, mask, gateway, DHCP state and DNS servers of every adapter.
3. Connect the laptop's Ethernet adapter to the Gateway's 1Gb ETH port. The Gateway must have power, or the adapter shows no link.
4. Find the adapter. Adapter names vary: Ethernet, Ethernet 2, or a USB adapter's own name. Unplug the cable and plug it in again. The adapter that changes to Connected in Settings, or to Up in the PowerShell command Get-NetAdapter, is the one to change.

A USB-C Ethernet adapter works if Windows has a driver for it. If Get-NetAdapter does not list it, or the link light on the adapter stays off, fix that before you change any address.

Set the static IPv4 address in Windows 11

1. Open Settings.
2. Select Network & internet.
3. Select Ethernet, then select the Ethernet network that shows Connected.
4. Beside IP assignment, select Edit.
5. Change Automatic (DHCP) to Manual.
6. Turn IPv4 on.
7. Enter 172.31.255.123 as the IP address and 255.255.255.0 as the subnet mask. If the field asks for a subnet prefix length, enter 24.
8. Leave Gateway, Preferred DNS and Alternate DNS empty.
9. Select Save.

Leave the network profile set to Public. Microsoft recommends Public for a network you first connect to, and you do not need Private to assign an address.

Set the address with netsh

The same change from an administrator Command Prompt, for an adapter named Ethernet 2:

netsh interface ipv4 set address name="Ethernet 2" source=static address=172.31.255.123 mask=255.255.255.0 gateway=none

source=static turns DHCP off on that adapter and removes its previous static addresses and gateway. The change persists after a restart unless you add store=active. Use store=active on a shared service laptop: a restart then puts the adapter back on its saved settings.

Verify the result

Run these commands in Command Prompt:

ipconfig /all
ping 172.31.255.1

In the ipconfig /all output, find the adapter you changed. A correct result looks like this excerpt:

Ethernet adapter Ethernet 2:

   DHCP Enabled. . . . . . . . . . . : No
   IPv4 Address. . . . . . . . . . . : 172.31.255.123(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :

If the adapter shows Media State . . . : Media disconnected, there is no link: check the cable, the port and the Gateway's power. (Duplicate) after the address means another device on the link already uses .123.

A ping reply proves that 172.31.255.1 answers on the link. It does not prove that Edge is running. Test the Edge port from PowerShell:

Test-NetConnection 172.31.255.1 -Port 8082

TcpTestSucceeded : True means Edge is listening. Open http://172.31.255.1:8082 in a browser and sign in. Edge uses TCP port 8082 by default. If the site has changed the port or turned on HTTPS, use the address in the commissioning record. Check that the Gateway identity shown in Edge matches the label on the Gateway.

Restore DHCP after a temporary connection

Put the adapter back on DHCP before the laptop goes back on an ordinary network. A laptop left on 172.31.255.123 gets no address from that network's DHCP server and has no route to anything else on it.

1. Open Settings, Network & internet, Ethernet, and the adapter you changed.
2. Beside IP assignment, select Edit.
3. Choose Automatic (DHCP) and select Save.
4. Check DNS server assignment. If it does not show Automatic (DHCP), select Edit beside it, choose Automatic (DHCP) and select Save.
5. Connect the laptop to its normal network. If Windows does not get an address, unplug the cable and plug it in again.
6. Run ipconfig /all. Compare the result with ipconfig-before.txt. DHCP Enabled must show Yes.

With netsh, from an administrator Command Prompt:

netsh interface ipv4 set address name="Ethernet 2" source=dhcp
netsh interface ipv4 set dnsservers name="Ethernet 2" source=dhcp

If the adapter originally had manual settings, enter the values from ipconfig-before.txt instead.

Static address or DHCP reservation

A manual address is stored on the Windows computer. A DHCP reservation is stored on the DHCP server. The computer stays on automatic addressing and always receives the same address.

On a managed network, use a DHCP reservation. The DHCP server then keeps control of the gateway, DNS and lease options, and the network owner can see the address in one place. Use a manual address on an isolated plant network with no DHCP server, or for equipment that must work before the DHCP server is available. For either, get the address, mask, gateway and DNS values from the network owner.

Do not use 172.31.255.0/24 on a site network unless the network owner has assigned that subnet for this purpose.

Troubleshooting a static IP connection

Windows shows a 169.254.x.x address

The adapter is still on automatic addressing. Windows found no DHCP server and gave itself an Automatic Private IP Addressing (APIPA) address from 169.254.0.0/16. This address cannot reach 172.31.255.1. Check that you saved the manual address on the adapter that has the cable, not on a different Ethernet adapter.

Windows saves the address but the Gateway does not answer

Check the link first: ipconfig /all must not show Media disconnected for the adapter. Check that the cable is in 1Gb ETH, not 2.5Gb ETH.

Then check the route. Run route print -4. The IPv4 route table must have one entry for network destination 172.31.255.0, netmask 255.255.255.0, gateway On-link, interface 172.31.255.123. A second entry for 172.31.255.0 on another interface means that another adapter or a VPN also uses this subnet, and Windows can send the traffic there.

Do not disable security controls indiscriminately. Test one cause at a time. Some VPN clients block all traffic to local subnets while they are connected: disconnect the VPN and run the ping again. If ping fails but Test-NetConnection 172.31.255.1 -Port 8082 succeeds, something on the path blocks ICMP; Edge is still reachable.

Windows reports an address conflict

Another device on the link already uses the address you entered. On a direct cable, the only other device is the Gateway at .1, so check that you did not enter 172.31.255.1 on the laptop. Choose another address from .2 to .254. Do not use .0 (the subnet address) or .255 (the broadcast address).

The Gateway address still does not answer

The Gateway may use an older network image, or someone may have changed its management address. Do not widen the laptop's subnet mask until something answers: a larger mask hides the real problem and can overlap other networks. Use the downloadable EPI-261-01 field guide for the one-page procedure, or contact EpiSensor with the Gateway serial number.