A problem easily stated, but seems much harder to solve.
We have Minecraft on two separate PCs, one desktop and one laptop. Both have wifi and wired ethernet, and we're trying to play the online games in "Realms". On the wired ethernet we can connect fine, but on the wifi it never works.
I'm pretty confident the issue isn't the PCs themselves: I've checked through the firewall settings and everything in quite some depth.
I've set up a basic Minecraft server online to do some testing and I can now get packet traces at both ends. The protocol in use is RakNet, which is UDP-based, and both the client and server can communicate - but it does appear some specific packets from the server to the client (message ACKs, which are a RakNet thing not the TCP ACK) are getting dropped. The RakNet client ends up just retrying the message continually because it never gets the ACK back.
I've factory reset the Home Hub, and there's no special settings on it whatsoever. The clients connect directly to it (wired or wifi). I've played around with lowering the MTU on both the client and the server, at the same time, but to be honest most of the packets are not big enough to trigger fragmentation anyway.
I realise this is a bit of a technical question, but does anyone have any ideas before I go to support? 🙂 Thanks!
I suspect this is the same as the problem I'm having, the DNS servers dont seem to be updating. I've got a dynamic DNS and it hasn't updated on the BT DNS servers yet after 5 days wheras all the other DNS servers I query (Google, Cloudfare etc) have.
However phoning the BT tech support they have no way to raise this as an issue with the engineers and just say 'log a call on the forums'
Sadly no, I'm not relying on Dynamic DNS for this. The bit on my home network is just regular Minecraft: the server is hosted in a DC elsewhere, it's not on the home network.
yes, but if the DNS entry is incorrect on the BT servers then it wont be contactable and wont function. The pc that works could possibly have it cached....
Oh, I see what you mean! No, the DNS is working fine - I have a packet trace and all the IPs are correct. The "connection" (it's UDP, so it's not really a connection) does work to begin with, but it consistently drops inbound RakNet Ack packets so the conversation never progresses. There's no failing DNS request.
Both machines have been rebooted, and I can switch from ethernet to wifi and back very easily - nothing changes from a DNS perspective. It works on ethernet, it fails on wifi 😞
ah, ok, so UDP is a 'fire and forget' protocol, unlike TCP. I'm not too au fait with settings in minecraft servers but if you can switch it to tcp I would reccomend trying it.
With Wifi there is more chance of it dropping particularly due to range and number of concrete pillars or brick walls between (which I'm guessing from your message you know already 🙂 )
IT's also possible that one of the ends of the wifi is either going into sleep mode or has a fault.
It's also possible that it's a windows setting. I for example have issues maintaining a connection to a work laptop through Wifi for RDP 3 seconds after the device boots, but no such issues connecting to it via ethernet... So depending on the box this may be a wifi device security setting issue.