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OS Name/Version: Windows 10/10.0.19045

Product Name/Version: (Always use the full version number - not ‘Latest’)
Problem Description:
Dayz server not showing in community outside local network and when connecting via IP there is an failure, Unable to connect to server, app id specified by the server is invalid
works fine on local network.

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Steps to reproduce:

  • Step 1
  • Step 2
  • Step 3

Actions taken to resolve so far: none

Hi Dale,

Thanks for reaching out about your DayZ server issues. Let’s tackle the connectivity problem first. It seems like the server is working fine on your local network but isn’t accessible from outside.

To start troubleshooting, we’ll first ensure that the server is properly listening on the ports that DayZ uses. Please follow these steps:

  1. Open a command prompt.

  2. Run the following command to check the server’s ports:

    ampinstmgr ports Decadeus

Please share the output of this command here. This will help us determine if the service is listening on the correct ports. Once we have that info, we can move on to the next troubleshooting steps.

Thanks for the quick reply

This is what get in command prompt

C:\Windows\system32>ampinstmgr ports Decadeus
[Info] AMP Instance Manager v2.4.6.6 built 05/10/2023 11:57
[Info] Stream: Mainline / Release - built by CUBECODERS/buildbot on CCL-DEV
[Error] No such instance matching name: ‘Decadeus’

Hi there, it seems there’s a little typing mistake in the instance name. Could you double-check the actual name of your DayZ instance in AMP and run the ampinstmgr ports [INSTANCENAME] command again with the correct instance name?

To find out the name of the instance, you can run the command ampinstmgr list in a command prompt and it will show you all instances. Then, use the exact name from the list to check the ports:

ampinstmgr ports YourInstanceNameHere

Please replace YourInstanceNameHere with the correct instance name you find and post the output here. This will help us get the correct port information. Thanks!

Ok got that

[Info] AMP Instance Manager v2.4.6.6 built 05/10/2023 11:57
[Info] Stream: Mainline / Release - built by CUBECODERS/buildbot on CCL-DEV
[Info] Port usage for DayZOriginal01 (DayZOriginal)
[Info] Instance is currently running.
[Info] LISTENING 8081 TCP (Core.Webserver.Port)
[Info] LISTENING 2302 UDP (GenericModule.App.Ports.$GamePort)
[Info] CLOSED 2303 UDP (GenericModule.App.Ports.$ReservedPort)
[Info] LISTENING 2304 UDP (GenericModule.App.Ports.$BattlEyePort)
[Info] LISTENING 27016 UDP (GenericModule.App.Ports.$QueryPort)
[Info] LISTENING 2305 UDP (GenericModule.App.Ports.$RCONPort)

Great, thank you for providing the port information for your DayZ instance DayZOriginal01. It looks like the game’s main port and others are listening, but the reserved port 2303 shows as CLOSED. This might be part of the issue for external connections, but I want to guide you through a couple of checks to make sure we cover all the typical obstacles to external access.

Please follow these steps:

  1. Firewall Rules: Verify that the firewall on your Windows machine has all the required ports open. You can do so by checking the inbound rules in the Windows Defender Firewall with Advanced Security.

  2. Port Forwarding: Make sure that your router has port forwarding set up for the ports used by your game server. This will usually include TCP/UDP ports 2302-2305, 27016, and possibly 8081 if you’re allowing access to the web admin interface from outside your network.

  3. Check connection internally: Attempt connecting to the server using another device that is on the same local network using the internal IP address and ports.

Once you have confirmed these details, we can discuss further troubleshooting steps if required. If you encounter any difficulty or have any questions along the way, let me know!

OK I have double checked my firewall rules, port forwarding and I can connect with 2 other PC’s on the same network

Thank you for confirming that, Dale. With local network connections working fine, the next step is to test external connectivity. Since you’ve already set up both firewall rules and port forwarding, let’s proceed with the following:

  1. Try connecting from a device that is not on your local network using your public IP address and port numbers.
  2. Ensure that you’ve set up port forwarding correctly for all the necessary ports on your router. It’s worth double-checking the IP address that the ports are being forwarded to—is it indeed the local IP of the server?
  3. Check if your ISP might be blocking any of the ports needed for DayZ. Some ISPs do block certain ports by default for security reasons.

If after all these checks, the server is still only accessible from within your network, we may need to consider the possibility of a “hairpin NAT” or “NAT loopback” issue with your router, which affects how devices on the local network can access the server using the public IP. Let me know once you have tried these and we’ll proceed from there.

We have tried to get another person connect from outside with the public IP on port 2302.
I use opnsense firewall and im pretty sure the port forwarding is setup correctly.
I have ask our ISP about blocked ports because were having game server issues and this is there response

Blocked Outbound Ports
TCP/25 (Except to our mail servers)

Blocked Inbound Ports





TCP/UDP 11211
If you need to port forward you might need to have to opt out of CGNAT

But i think thats only for the default blocked ports

Thanks for doing those checks, Dale. It doesn’t look like any of the ports your DayZ server would be using are being blocked by your ISP, so that’s good news. However, there might be a possibility that your connection is under Carrier-grade NAT (CGNAT), which can present issues for port forwarding because your public IP is shared among multiple customers.

Since your ISP mentioned opting out of CGNAT for port forwarding to work correctly, please confirm whether your public IP address is unique to you. If you’re under CGNAT, even with perfect port forwarding and firewall rules on your end, external players will not be able to reach your server. If you have not opted out of CGNAT, I recommend you contact your ISP to request this, explaining that you need a unique public IP for your game server.

Let’s also double-check that the IP your port forwarding rules are pointing to is still correct:

  1. On your server host machine, open a command prompt.
  2. Run ipconfig and note down the IPv4 address.
  3. Make sure this IPv4 address matches the one used in your port forwarding rules.

Once you’ve confirmed these details and if you’re sure about the correct port forwarding setup, we can further investigate if there might still be issues related to hairpin NAT or something else.

Let me know how it goes with your ISP or if there are any discrepancies in the port forwarding IP address.

The port forwarding IP is correct for the server PC.
We have static IP set and it says that GNAT will be automatically opted out.

Thanks for confirming those details, Dale. It’s reassuring to know that you have a static IP and are not behind CGNAT, which means we can rule that out as a potential issue. Given that, and since your local connections are working correctly, it sounds like we’ve narrowed it down considerably.

Now, the message regarding the “app id specified by the server is invalid” leads me to think there could be an issue with the server configuration, specifically possibly related to the Steam App ID setup.

In DayZ, the Steam App ID tells Steam which game the server is for, and if this isn’t set correctly, or there’s a mismatch, it will lead to the error message you’re seeing.

Here’s what we can do to check this:

  1. Verify that your DayZ server configuration has the correct Steam App ID. It should match the App ID for a DayZ dedicated server.

  2. Make sure that the server is not running in any “offline” mode, as this can sometimes trigger such errors.

  3. Restart your DayZ server after any configuration changes to ensure they take effect.

Lastly, run ampinstmgr lastlog DayZOriginal01 on the server to check the most recent logs for any errors or warning messages that might shed light on the issue.

Could you check these and update me on what you find?

Apollo, stop, you have no idea. App ID is OK, ports are OK

OP - how are you connecting in the client?

Hi Greelan,

We are working through the troubleshooting process systematically. However, I appreciate your input. Let’s focus on how Dale has been connecting to the server externally.

Dale, could you please provide more details regarding the method you are using to connect to your DayZ server from outside your network? Are you using the in-game server browser, direct IP connection, or any other method? This could help us narrow down where the issue lies.

Where do i find the steam app ID in the config and how do i check its not running “offline” mode

Ignore the bot

Show me your port forwards

Hi Dale,

The Steam App ID for the server is usually set in a configuration file or as a start-up parameter for the server. Here’s what you can check:

  1. If your server uses a configuration file, look for a parameter related to the Steam App ID. This is sometimes named SteamAppId or similarly. It should be set to the correct value for DayZ, which you would find in its documentation or official forums.

  2. For the “offline” mode issue, in AMP, “offline” mode refers to “Standalone Mode” for your Minecraft instances. For DayZ, make sure that the server settings don’t have you in some sort of LAN-only mode, which might be described in the server documentation.

To proceed with verifying these settings:

  • Navigate to the server’s configuration file and check for the SteamAppId setting.
  • Also, review the entire config file for any option that might restrict the server to LAN or internal network connections only.

Remember to restart your server if you make any changes to the configuration file.

As for Greelan’s request, it’s certainly your choice if you wish to share your port forwarding setup, but I should remind you we should keep focused on the information at hand and on solving the specific issue you’ve reported. We can certainly proceed with the steps I mentioned above without sharing your port forward settings publicly.

Let me know once you’ve checked the Steam App ID and server connection settings so we can proceed to the next step if necessary.

Im using the dayz launcher but it cant find my server so they have to use the connect directly with IP

Thanks for clarifying how you’re attempting to connect. If your server isn’t showing up in the DayZ launcher server browser and requires direct IP connection, there are a few reasons this might be happening, but since we’ve already checked several network-related aspects, it could be a problem with the server’s visibility settings.

Here are a couple of things we can verify:

  1. Server Visibility: Ensure your server is set to be visible in public server lists. There might be a setting in the server configuration for isPublic or similar to make sure it’s indeed meant to be shown on community listings.

  2. Steam Query Port: Double-check that the Steam query port (usually 27016 for DayZ) is correctly forwarded in your router and that there are no typos or incorrect IP addresses specified. This port is crucial for the server browser functionality.

  3. Direct Connect: When using the direct connect method, you must use your public IP followed by the game port (for example Verify with your friend that they are entering the address correctly.

Could you check on your server’s visibility settings and ensure that the query port is indeed configured correctly? If you’re unsure about where to find these settings, they’re typically in a server config file or set as startup parameters for the server. Let me know what you find!

Thats the rule i made in forwarding