Host Unreachable issue

[Mailuki]

In Multiplayer, Ylands relies on Steam networking to both establish connection and send data between Ylands client and server. The Host Unreachable error indicates that Steam networking was unable to establish connection between the game client and remote game server.
In general, Steam networking will be able to establish connection without issues, but sometimes firewall or specific configuration of network environment of the client or server may affect it.

Make sure all ports that Steam uses are open https://support.steampowered.com/kb_article.php?ref=8571-GLVN-8711.

[Superjonin]

Doesn't help. Is not our ports problem, It's the game, how's need be fixed. I'm playing since the game start in Steam, and same for my friends, but 2 of 6 guys, can't play in our dedicated server. (Yes, dedicated, we pay money every mouth for this game). What can we do so? No one wanna help us?

PS: Why we need to open any ports? I never see something like this...

[Elindor]

let's say I don't have a clue what those ports are, and how to find them ... and what to do with them ... Fix your dang game ... it cost money ...

[Kyuo]

Ok, done all, nothing work. I got a dedicated server and its nearly unplayable. Ater 5-15min Playing on Server i got kicked out with that message. Its not the Problem from Client.

[Marvy]

yeah tried all but it doesnt seem to be a port problem,
3 of us play, if we create a new world (any of us) we can all connect no problem,
if it crashes for any reason and we try to log back in we get the host unreachable thing,
makes it unplayable as we dont wont to spend a pile of time building a world only to get to a point we cant get back in :(

[Pondscum]

i'm with marvy here. I have 5 other people so far that all have purchased this amazingly interesting game...But moving on from this multiplayer is totally messed up even on your own dedicated servers...when hosting a private game among friends it's exactly like what marvy described...fresh start and we can all get on....usually once on if anyone disconnects for any reason the game is shot...they can't get back on it's host unreachable. It feels like when you're joining this game you're downloading not just a chunk of the map, you're downloading the entire known world and it jams my horrid internet through the roof until it decides it's host unreachable. I'm not the only one of the 6 people having this trouble, everyone else ... everyone cannot join a session that is in progress.

Now for your servers we tried north america exploration 29...well we built a ship and ran for another island due to some people that saw us online and came to attack us...not realizing we were together it didn't work out well for them but as we arrived at our new home island problems started happening that were more serious than anything we had experienced thusfar. Initially the only problems we encountered were whenever someone would join it would lag out the server causing us to either repeatedly pick an item for oh 30 seconds or more...occasional server stutter...but once we made it to the desert island we couldn't mine as nothing would show up on the ground...I could do nothing productive and the textures on the ship and crabs i saw went black for some reason making it unplayable...even relogging wouldn't fix the problems and we finally had to give up.

I connect to these people on so many games and never...ever...have a problem. I read something posted today about it's our problem...our ports...our firewalls....I know i'm not the game designer...i'm not the programmer but thinking logically we never, ever have this problem with any other game. Add to it if it was our firewall and ports how on earth do we all initially join with little problems other than jamming up the game while each of us joins? Wouldn't it stop us from the beginning from joining together? I don't know if it's even possible but it really feels like if it doesn't load the whole game in a set time it just times us out and ships us back to main screen.

[Soondead]

The problem occurs spontaneously during gameplay and is not caused by firewalls blocking the packets at our end. Both my client and dedicated server are running behind the same Linux based firewall where incoming traffic to UDP ports 2500-2509 are forwarded to the server which has a static IP address. The client also has a static IP address and there are no packets being blocked in either direction. Like others have pointed out, this seems to be a problem specific to Ylands and this would indicate that there is a problem with either the server or the client, and not the network itself.

The most likely cause is random packet loss and/or packet reordering across the internet, which any application that uses UDP must be able to cope with. If not, the application is squarely at fault.

[NerdyDavros]

There are a lot of valid points here.
I also regularly play multiplayer with my friends and there is one who seems to specifically get this issue a lot. What we have noticed is that the game seems to use a lot of bandwidth (more so with the upload), and when there are multiple connections to the host, there seems to be an issue with the data bottle-necking somewhere. Also, because so much data is constantly sent back and forth, it makes it more susceptible to packet loss. We have to try and get around these issues by preventing multiple people from joining at once and by getting those who have the greatest difficulty with the connection to join first.

This leads me to believe that the fault is on the games side and not the users side. If the developers get the game to send bits of the world over in smaller chunks while preventing it from re-sending the same data, it should ease up the bandwidth. From what I can see, the bulk of the world gets saved on the hosts side and not the clients side, and thus it would probably be more beneficial to allow saving of the world on both sides. That would probably also help prevent the issue with the maps not saving for non-host players. My current multiplayer world size is about 28MB and even though it isn’t that much, it adds up to a lot of data if it constantly gets sent to multiple connections. This can become even worse if the data is routed through multiple points before reaching it’s destination.

Despite all this though, my friends and I are having a tremendous amount of fun. So I thank the developers greatly for all the hard work that they have and will put into this game.

[Zyenna]

This error comes when I want to start the game. I tried it in the offline modus but nothing happens.

[Soondead]

Transferring huge chunks of data using UDP just isn't what UDP is designed for. Invariably, it forces devs to try and recreate decades of research that went into the making of TCP by implementing a reliable protocol on top of UDP. This begs the question; why oh why don't they just use TCP for the big chunks and UDP for the realtime stuff?

[Kiiyuu-]

Just out of curiosity... has this solution actually fixed the issue for anyone?
I've been searching desperately for a working solution. The devs all seem to point to this thread, but the suggested fix does not seem to work at all.

[Soondead]

Well, if the ports to the client or server are closed (blocked) then it won't ever work until you open them.

If it works most of the time but you get random drops, then no, the situation is unchanged and the solution does not apply.

[Kiiyuu-]

I have tested this with several new maps on a few (reliable) networks. With ports on both server and client open or closed, the result is the same.
That result being... first 6-10 hours of gameplay, everything works 100%. The players are able to leave and reconnect at will with no issues. As soon as the map gets to a certain size with an amount of entities on it, the players one by one get disconnected and are prevented from reconnecting no matter how many attempts are made. All reporting "Host Unreachable".

I'm not sure about "random drops", in our case, we either can connect or can't connect, with no in between

[Zerpyn]

Same problem.

[Pondscum]

We had hope this issue was addressed in these patches but sadly no...started a game with some of the friends and after a while disconnected and attempted to reconnect and hello host unreachable my old friend.

[NerdyDavros]

Finally managed to put aside an hour to do some data monitoring with a program called GlassWire. Couldn’t do as much testing as I wanted tonight, but hey, here are some numbers for now. If all goes well you can check out the results in the links bellow.

For reference, my host file save is currently 29.4MB. I had 1 user join the host twice (second time after their character froze) and a second user join in shortly after. It took an average of 2min for all the data to be sent to each user. All of the following upload and download numbers belong to the “Steam Client Bootstrapper”. From what I can tell, this is what seems to be handling the multiplayer side of the game (also the devs said they use steam to handle the multiplayer).

From what I can see, each time the first user joined 52MB of data was uploaded, and around 62MB for the second user (will do more testing later to verify this). After the users finished joining, the connection seemed more stable uploading only 1.3MB of data within 1min. The download for connecting 2 clients was on average half of the stable upload with the odd spike. These average download and uploads numbers were about half that amount when there was only one client connected.
The entire duration of the test was about 1hr + 5-10min. Over that period of time 34.3MB was downloaded and 246.5MB was uploaded. If you remove the 166MB of file uploads from when the clients joined the host, it comes to about 80MB of uploads for the duration of the test for 2 clients.

Now, about the whole issue of UDP and TCP. To be honest, I haven’t had enough time to verify which connections this game is using, but Mr. Google has hopefully helped me become enlightened enough to give some input. To sum it up, it is best that this game stick with only using UDP because by using only TCP or a mixture UDP and TCP, it can cause instability issues and massive pings (TCP dissrupts UDP packets). If you want further reading, try these links:
https://gafferongames.com/post/udp_vs_tcp/
https://1024monkeys.wordpress.com/2014/04/01/game-servers-udp-vs-tcp/

If you want links to my screenshots of GlassWire, here they are...

• First Users Connection[i.imgur.com]
  
• Second Users Connection[i.imgur.com]
  
• All 3 Connections[i.imgur.com]
  
• Stable Connection[i.imgur.com]
  
• Entire Test[i.imgur.com]