FYI
I can work with you on any configuration changes on the server or network that you may need to test OR to create additional logging info, etc.

@Geez This issue is NOT caused by "A server ping exceeding 999 milliseconds when hosting a LAN is a normal occurrence. This is because the server is not accessible from the internet and we cannot accurately assess ping times using private IP addresses."

It is not a duplicate of T184790: Self hosted server always show "high ping server" in server browser

OPEN this case please and actually read the information presented in this BUG.
The title states "Publicly available" and this issue is not resolved.

In T186386#2703831, @priglmeier wrote:

@Geez This issue is NOT caused by "A server ping exceeding 999 milliseconds when hosting a LAN is a normal occurrence. This is because the server is not accessible from the internet and we cannot accurately assess ping times using private IP addresses."

It is not a duplicate of T184790: Self hosted server always show "high ping server" in server browser

OPEN this case please and actually read the information presented in this BUG.
The title states "Publicly available" and this issue is not resolved.

Thank you for clarification, forwarded to the dev team and we will see what we can do.

Example 1): seems to be correct behaviour so we do not have anything to say to that

on Example 2), there are some points:

1: LAN will never work in that case if your router does not support NAT Loopback because you would need to connect to your server with your public IP address since we dont support direct connect to specific IP address so you cannot use your private IP address to connect to your server.

2: Regarding WAN users..
a) Since you can host Arma 3 server without issues then you most probably have public IP address provided by your ISP so no issue there.
b) You did not provide any logs from Server nor Client so not much for us to go by

We are bit confused by

The Public address is set to the Port Forwarded IP - LAN address 192.168.1.223

and

The Public address is set to the Public IP

Does that mean that in example 2, you have removed port forwarding?

Our only guess right now is you are confused as to how it should be configured.
If your server is running on machine with LAN address 192.168.1.223 then you should port forward correct port to that IP and then in server config set your public IP address.

Alright. The issue remains the same though. In both configurations either the WAN or LAN clients con't connect as expected.
Let's focus on Example 1 since you reported this should work properly.

I am using this configuration currently:
Example 1: Public address set to LAN IP using port forwarding.
The server bind address is set to 0.0.0.0 (as instructed)
The Public address is set to the Port Forwarded IP - LAN address 192.168.1.223

A local (LAN) client can connect. The ping is listed as 999ms even though the correct ping time is about 30ms-40ms.
Other players can't connect to the server due to the false high ping of 999 and the Kick cause code: group=1 REPLICATION', reason=3 'CONNECTION_FAILURE' Check console log for more details.

Questions:
The reported ping of 999 appears to be false.
So why can't WAN clients connect as expected?

What causes the "Kick cause code: group=1 REPLICATION', reason=3 " error?

If there is a dedicated server configuration fix. What is it?
The server is open to the public and is also hosting an Arma 3 dedicated server which works 100%.

I can provide logs if you need them. What files do you want me to add here?

What we meant that behaviour you observed is correct, that is how it should currently behave.

publicAddress in server config is IP players will use to connect to the server. So if you set that IP to your private LAN address then ofcourse people from WAN cannot connect. They are not in your LAN.
Ping 999+ is because that ping is measured against ping site which is assigned based on geolocation of IP address you set in publicAddress which we cannot determine by private LAN address so it defaults to no ping site and ping cannot be measured.

As to which log then console.log
Ideally from both server and client that is trying to connect from WAN

This is only partially correct.

Port forwarding is configured and is working properly.
The LAN address should not matter. Port forwarding is set properly for Arma Reforger.

PORT FORWARDING CONFIG
Arma-Reforger Settings

FROM Any
PORT 2001,17777,27015
FORWARD IP / PORT 192.168.1.223:2001,17777,27015

Arma-Reforger-TCP
FROM Any
PORT 27015,27036
FORWARD IP / PORT 1192.168.1.223:27015,27036

So both LAN and WAN clients should be able to connect without any issues like the Arma 3 server / clients.

If the WAN client does not care about the reported ping being 999 (or ignores this), then the WAN client should be able to connect properly.
Why does the WAN client not connect as expected?

In T186386#2703867, @priglmeier wrote:

This is only partially correct.

Port forwarding is configured and is working properly.
The LAN address should not matter. Port forwarding is set properly for Arma Reforger.

PORT FORWARDING CONFIG
Arma-Reforger Settings

FROM Any
PORT 2001,17777,27015
FORWARD IP / PORT 192.168.1.223:2001,17777,27015

Arma-Reforger-TCP
FROM Any
PORT 27015,27036
FORWARD IP / PORT 1192.168.1.223:27015,27036

So both LAN and WAN clients should be able to connect without any issues like the Arma 3 server / clients.

If the WAN client does not care about the reported ping being 999 (or ignores this), then the WAN client should be able to connect properly.
Why does the WAN client not connect as expected?

if you set publicAddress to 192.168.1.223 WAN clients will try to connect to 192.168.1.223:2001 then it is obvious that they cannot join because they are trying to connect to your private address and not public address.

and port forwarding seems... correct
though you set multiple ports which are not used by Reforger.

only UDP on 2001 is important and optionally 17777 for A2S protocol which is not enabled by default and if you do not know what it is then you can just ignore it

However, if you set publicAddress to your private IP address then it will not and cannot work for WAN clients...
This is not debatable as it simply cannot work.

OK. I think there has been some more confusion here, but I will clarify. :)

So we are really talking about Example 2 as the only viable option.

Step 1 - Set Public IP
Example 2: Set public address to Public IP which is 75.168.141.218 the server is MNeapolis
The server bind address is set to 0.0.0.0 (as instructed)
The Public address is set to the Public IP 75.168.141.218
I removed the un-needed ports from the config.

PORT FORWARDING CONFIG
Arma-Reforger Settings - UDP

FROM Any
PORT 2001
FORWARD IP / PORT 192.168.1.223:2001

Step 2 - Attempt client connection from Arma Reforger server browser
I can see the server in the server browser on the client.
Yes, the ping time is correct.
I attempt to join the MNeapolis server.

The client spawns this error and will not connect: "Kick cause code: group=1 REPLICATION', reason=3 'CONNECTION_FAILURE' Check console log for more details."

Client connection test 2 - Try a direct connection

Use the Direct connect option and the Public IP 75.168.141.218
The client spawns the same error repeatedly.

Client side logs show the same error and not much else for the above 2 examples:

10:45:24.989 SCRIPT : Kick cause code: group=1 'REPLICATION', reason=3 'CONNECTION_FAILURE'
10:45:24.991 SCRIPT : [SCR_ConfigurableDialogUi] presetsResourceName: {D3BFEE28E7D5B6A1}Configs/ServerBrowser/KickDialogs.conf, tag: REPLICATION_CONNECTION_FAILURE, customDialogObj: NULL

Current client logs, 7-zipped.

Server logs attached

Hello priglmeier.
These do not seem to be our logs but rather steamcmd logs, we need console.log from the server similarly like you sent the client logs.

Alright. My bad. I will attach the server logs

Seems like your server is running -logLevel error which makes log from server which makes us unable to get much info since there are only errors present.
Also it is not good practice to run server with only errors so we would recommend removing it and not using it like that in future

Which log level do you recommend then? Normal?

I re-ran the same client connection test. Same error on the client around Tue, Nov 19, 12:30-40 PM
New server logs attached with Normal logging.
Then I stopped the server afterwards.