Alpaca Server on Another Windows Machine

Follow these steps when the Alpaca server (ASCOM Remote, Alpaca Simulators, or any Alpaca-compatible server) runs on a Windows machine different from the one running Arcsecond.local, both on the same local network.

Everything below is done through graphical interfaces. No terminal command is required.

Throughout this page:

• 192.168.1.42 stands for the IP address of the Windows machine running the Alpaca server.
• 11111 stands for the port of the Alpaca server (the ASCOM Remote default; Alpaca Simulators use 32323).

Replace both with your own values.

1. Note the IP address of the Windows machine

On the Windows machine running the Alpaca server:

1. Open Settings → Network & Internet.
2. Click Wi-Fi or Ethernet, depending on how the machine is connected.
3. Click the name of the network, then scroll down to IPv4 address.
4. Write that address down (e.g. 192.168.1.42).

2. Fix that IP address

1. On the same page, next to IP assignment, click Edit.
2. Choose Manual in the drop-down.
3. Turn IPv4 on.
4. Fill in:
   • IP address: the address noted at step 1.
   • Subnet mask: 255.255.255.0.
   • Gateway: your router's address (usually the same address ending in .1, e.g. 192.168.1.1).
   • Preferred DNS: your router's address, or 1.1.1.1.
5. Click Save.

TIP

If your router offers a "DHCP reservation" page, reserving the address there works just as well, and leaves the Windows settings untouched.

3. Set the network profile to Private

1. Open Settings → Network & Internet.
2. Click Wi-Fi or Ethernet, then the network name.
3. Under Network profile type, select Private network.

4. Make the Alpaca server listen on the network

ASCOM Remote

1. Start ASCOM Remote Server.
2. Click the Setup button.
3. Open the Server Configuration tab.
4. In Server IP address, select the address noted at step 1 (192.168.1.42) — not 127.0.0.1 and not localhost.
5. Leave Server IP Port at 11111.
6. Tick Enable Alpaca Discovery and Management Interface.
7. Click OK.
8. A dialog titled "HTTP listen permissions required" appears. Click Yes, then Yes again on the Windows permission prompt. The server restarts on its own.
9. Back in the main window, click Start: the status must read Remote Server Up. Click Connect to connect the devices.

Alpaca Simulators

1. Start ASCOM Alpaca Simulators.
2. Open the web page it displays (by default http://localhost:32323).
3. Go to Server Settings.
4. Set the Server IP Address / binding to All interfaces (0.0.0.0), or to 192.168.1.42.
5. Leave the port at 32323, and tick the Alpaca Discovery option.
6. Click Save, then restart the application.

5. Open the port in the Windows firewall

When the Alpaca server starts for the first time, Windows may display a Windows Security Alert. If it does:

1. Tick Private networks.
2. Click Allow access. You are done with this step.

If no such dialog appeared, or if you clicked Cancel, create the rule by hand:

1. Press the Windows key, type firewall, and open Windows Defender Firewall with Advanced Security.
2. In the left column, click Inbound Rules.
3. In the right column, click New Rule….
4. Select Port, click Next.
5. Select TCP, then Specific local ports, and type 11111. Click Next.
6. Select Allow the connection. Click Next.
7. Tick Private only (untick Domain and Public). Click Next.
8. Name: Alpaca server (TCP 11111). Click Finish.

Repeat steps 3 to 8 a second time for Alpaca discovery, changing two values:

• At step 5, select UDP and type 32227.
• At step 8, name the rule Alpaca discovery (UDP 32227).

WARNING

If a third-party security suite is installed (Norton, Kaspersky, Bitdefender, ESET…), it has its own firewall. Open its interface and allow the same ports there too.

6. Check the connection

On the machine running Arcsecond.local, open a web browser and go to:

http://192.168.1.42:11111/management/apiversions

A short text response such as {"Value":[1],...} means the connection works. If the page never loads, go back through steps 4 and 5.

7. Register the server in Arcsecond

1. Open Arcsecond.local and go to the Control Room.

2. Click Start Registration… (or open the device registration panel from the Equipments tool).

3. On the Alpaca Server step, in the field following http://, type:

   192.168.1.42:11111

4. Click Check. The server name, manufacturer and number of devices appear.

5. Click Register Server.

6. Click Next and continue with the Alpaca Devices, Telescope & Mount, Other Equipments and Observing Setup steps.

WARNING

Do not enter localhost or 127.0.0.1 in that field. Those addresses point to the machine running Arcsecond.local, not to the Windows machine hosting the Alpaca server.