Friend gets disconnected from dedicated server

[Sincop3]

I managed to get to work a dedicated server running with Hamachi, after messing with the firewall and the settings i have all of it down, in fact another guy can join without problems, but another friend get kicked 30 second after joining with a "losing connection to the host" and a timer ticking down, we tried everything expect port forwarding his router with 42420

[Teh Pizza Lady]

Are you or your friend:

• using a mobile hotspot or wifi on a college campus?
• configuring Hamachi correctly? It uses UDP ports that are not open by default

College campus networks are NOTORIOUS for implementing CGNAT which interferes with the network tunnels that Hamachi creates. They also like to implement deep packet inspection algorithms which interfere with Hamachi tunnels. Back in the day we used to use Hamachi to play games and we could only get it to work if everyone was either on the college campus or off the college campus, but not if there was a mixture of the two. Try as we might we could not get the network to cooperate. I think we even took it up with the college IT department and the answer was basically an instant "no".

If you are on a college network or one of your friends is on a college network, the solution is to open port 42420 on the router of the person hosting the multiplayer game (NOT ON THE CAMPUS NETWORK) and do the appropriate port forwarding there. Then sign up at NoIP.com and get yourself a dynamic DNS name that you can share with your friends. It should work then.

Edited October 24, 2025 by Teh Pizza Lady

[Sincop3]

5 hours ago, Teh Pizza Lady said:

Are you or your friend:

• using a mobile hotspot or wifi on a college campus?
• configuring Hamachi correctly? It uses UDP ports that are not open by default

College campus networks are NOTORIOUS for implementing CGNAT which interferes with the network tunnels that Hamachi creates. They also like to implement deep packet inspection algorithms which interfere with Hamachi tunnels. Back in the day we used to use Hamachi to play games and we could only get it to work if everyone was either on the college campus or off the college campus, but not if there was a mixture of the two. Try as we might we could not get the network to cooperate. I think we even took it up with the college IT department and the answer was basically an instant "no".

If you are on a college network or one of your friends is on a college network, the solution is to open port 42420 on the router of the person hosting the multiplayer game (NOT ON THE CAMPUS NETWORK) and do the appropriate port forwarding there. Then sign up at NoIP.com and get yourself a dynamic DNS name that you can share with your friends. It should work then.

I already opened my router to 42420 in TCP and UDP, but my friend can't since he cant get the credentials i will attach the info the server gives me when my friend is trying to connect, she is using a wi fi connection but the router is not on her floor and there is no way to do port forwarding, server did get her UDP but after some seconds disconnects her

[Sincop3]

She managed to enter 1 time tonight but a message pops up "Host not responding" and then kicks her out

[Teh Pizza Lady]

So to be clear you are not on a college campus, you run the server, and your friend is... where? i'm just trying to understand the setup. She could also just not have Hamachi setup correctly. I don't know what you don't tell me haha.

[Sincop3]

I run the server and my friend is on Hamachi network everything is fine, i can ping her, diagnostic tool is not showing any problem, she from Italy as i am, but we don't live close

[Thorfinn]

6 hours ago, Teh Pizza Lady said:

College campus networks are NOTORIOUS for implementing CGNAT which interferes with the network tunnels that Hamachi creates. They also like to implement deep packet inspection algorithms which interfere with Hamachi tunnels.

This is true of a lot of wifi, particularly the "free" ones. Even the moderately high end Hilton and Hyatt-Regency hotels do it. No one wants to have his company's wifi bill go up due to gaming, any more than from pron.

[Teh Pizza Lady]

7 minutes ago, Sincop3 said:

I run the server and my friend is on Hamachi network everything is fine, i can ping her, diagnostic tool is not showing any problem, she from Italy as i am, but we don't live close

If you own/control your own router and she does not, then you can setup the port forwarding, there shouldn't be any reason you cannot use a dynamic DNS service like NoIP.com instead. It won't rely on whatever weirdness is effecting Hamachi, and since you're only playing with friends, you don't have to worry about someone else getting your IP address.

I strongly recommend giving it a try and seeing if the problem is different or goes away entirely...especially since you are both in the same country.

[Sincop3]

i did set up the port forwarding on my end days ago, in fact only 1 person can join other people get the same problem, "host not responding" when they are able to get inside, or get blocked in loading the world from the VS menu, we are going to try the noIP.com method for now and see how that goes... do you have a tutorial for using noIP.com? and we still need to have a dedicated server on right?

Edited October 24, 2025 by Sincop3

[Teh Pizza Lady]

2 hours ago, Sincop3 said:

do you have a tutorial for using noIP.com?

1. Create account or sign in if you already have one
2. Click DDNS & Remote Access in the left <<< menu
3. Click DNS Records
   
4. Click the green Create Hostname button
   
5. Enter your desired host name. I put Sincop3_VS as an example. You can choose whatever you want. I chose serveminecraft.net as the domain because there is no servevintagestory.net. Make sure your IP address is correct. Check the Enable Dynamic DNS option.
6. Click the green Create with DDNS Key button
   
7. Download the DDNS client and install it. When it runs, allow it to simply run in the background.
   

 

This will help you ensure that your DNS record now always stays up to date with your IP address.

Make sure your ServerURL and IP entries in your serverconfig.json file are 'null'

With luck, it should work, but if not, then you'll be back here for more help!

[Sincop3]

12 hours ago, Teh Pizza Lady said:

1. Create account or sign in if you already have one
2. Click DDNS & Remote Access in the left <<< menu
3. Click DNS Records
   
4. Click the green Create Hostname button
   
5. Enter your desired host name. I put Sincop3_VS as an example. You can choose whatever you want. I chose serveminecraft.net as the domain because there is no servevintagestory.net. Make sure your IP address is correct. Check the Enable Dynamic DNS option.
6. Click the green Create with DDNS Key button
   
7. Download the DDNS client and install it. When it runs, allow it to simply run in the background.
   

 

This will help you ensure that your DNS record now always stays up to date with your IP address.

Make sure your ServerURL and IP entries in your serverconfig.json file are 'null'

With luck, it should work, but if not, then you'll be back here for more help!

thank you so much we managed to make this work!

[Teh Pizza Lady]

5 hours ago, Sincop3 said:

thank you so much we managed to make this work!

I'm so glad!