DNS resolution not working for one player

[Weissrolf]

One of my players cannot join my LAN game via DNS resolution, he has to enter my IP address instead. The same player can join via Classic, though.

Another player stated that he experienced DNS problems using the same carrier (and thus switched his DNS to Google), so I suspect that Classic may use a cached DNS entry where Unity does not?!

[Sulimo]

I don't think Unity uses any DNS. It is all 'Join by IP and Port'. There is no option to join by DNS that I have ever seen.

Classic had the random name generator that SmiteWorks ran, but it is not used for Unity from what I remember them saying.

https://i.imgur.com/WNerrtt.png

[Weissrolf]

You can just enter a domain name into the <IP Address> field and it works fine for everyone but one of my players. Since Classic does work on the same players computer there has to be something different in how Unity handles DNS.

[Sulimo]

I do not think that is supported.


Applications do not 'handle' DNS, that is done at a different layer of the network stack. The application passes the request to the OS which handles the lookup.

Can your player ping that DNS entry from a command line?

[Weissrolf]

I will check with him tomorrow. But as I wrote before, he can use the same domain name via FGC while FGU fails. And everyone else can use the domain name in Unity just fine (including a Linux user), it's just this one player who has issues. My current assumption is that his provider's DNS server did not get the latest dynamic DNS update and Classic gets the DNS entry from Windows' DNS cache, while Unity does not.

He did not notice any other DNS troubles on his machine, so at this point it is a Unity vs. Classic thing.

[Carlos]

One of my players cannot join my LAN game via DNS resolution, he has to enter my IP address instead. The same player can join via Classic, though.

Another player stated that he experienced DNS problems using the same carrier (and thus switched his DNS to Google), so I suspect that Classic may use a cached DNS entry where Unity does not?!


Is the player physically on the same network switch as you are?
Is the player using your DHCP to configure their system?
What does "ipconfig", run at cmd.exe prompt, say about all the system interfaces?
What does "ping -4 SERVER" (where "SERVER" is the name of the system you expect the player to connect to), run at cmd.exe prompt, print?


FGC does not cache DNS entries beyond any caching the OS uses, and I know this because I use short 60s TTL so I usually update my DNS dynamically and within 60s FGC correctly connects to the new host.

I've been using FGC and FGU on rather complicated network setups without any problems.

There is a lot that can go wrong with network configuration that is unrelated to FGC or FGU.

Answering some basic network questions might help us help you.

[Weissrolf]

The player is not on my network switch, he is in another town and on another provider. Since his provider is Vodafone (who bought Unitymedia) I suspect that he is on a cable connection via DSLite (IPv4 tunneled via IPv6). Maybe Unity uses IPv6 instead of IPv4 on his setup. At this time I cannot get any more information from him, but have to wait until tomorrow evening.

What I do know is that Classic worked when Unity did not. We tried both back and forth. This is why I suggested that Classic might make use of the OS DNS cache while Unity might now.

[Carlos]

The player is not on my network switch, he is in another town and on another provider. Since his provider is Vodafone (who bought Unitymedia) I suspect that he is on a cable connection via DSLite (IPv4 tunneled via IPv6). Maybe Unity uses IPv6 instead of IPv4 on his setup. At this time I cannot get any more information from him, but have to wait until tomorrow evening.

What I do know is that Classic worked when Unity did not. We tried both back and forth. This is why I suggested that Classic might make use of the OS DNS cache while Unity might now.

The "Join by IP and Port" text is being fed directly to the OS for hostname resolution and connection and it will accept FQDN (verified working just now for IPv4 from ISP), IPv4 (verified working just now for local and external) or IPv6 (verified does NOT work to connect to link-local address, though I expected it should work).

The problem is going to be on the DNS end. If you specify an FQDN but your DNS server returns an IPv6 address by default and IPv6 routing doesn't work then that won't work.

Without the exact details of which DNS server he is using, and which query is being made, there are a lot of variables.

Certainly FGC and FGU are different, they likely use different OS APIs to do hostname resolution (given that FGU is IPv6 capable) so they are going to behave slightly differently.

When your friend connects to your system FGU will show the fully resolved name in "()" after the "FQDN:PORT" part so you'll know what the result of the DNS server was to the client.

Example: 41163

Good luck with debugging.

[Weissrolf]

We will see tonight. I suspect IPv6 being used, which does not resolve the DDNS name to my IP despite the Synology server listing the IPv6 IP properly in its own DDNS settings. So it's likely a combination of my Synology not properly settings up IPv6 DDNS and his computer using IPv6 when Unity is used. He can connect via direct IP number until we can resolve this.

We can also give the cloud connection a try later on, but at this time it's just one more thing that can go wrong and port forwarding is already set up anyway.