Intermittent "Cannot establish connection to the server"

[auhmaan]

I've been having difficulties when trying to get the list of multiplayer servers to join, where I'm presented with the message "Cannot establish connection to the server" after a few seconds. I've looked throughout my computer and router settings in case something was wrong on my side, but everything seems to be working properly (I can see on the router outbound entries of connections to a server that I assume is the used by the game to get the multiplayer server list [base d on the information given by Windows Resource Monitor], but no inbound entries).

In an attempt to make sure the game files were okay, I verified the Steam game files, and deleted the "SimKol" folder for good measure, and it worked, but only once. If it's on my side, I'm open to try other solutions.

I've attached the last log file the game generated.

SimRail_log_2023-06-29_16-40-50.txt

[auhmaan]

It seems the culprit, in my case, was IPv6. After disabling it (Control Panel > View network status and tasks > "Active network" > Properties > Uncheck "Internet Protocol Version 6 (TCP/IPv6)") ir started working correctly every time (for now, it seems).

Should've noticed sooner since in Windows Resource Monitor, SimRail was creating connections with IPv6 addresses, and not IPv4.

Attached is a screenshot of where to find and uncheck the entry, if it is happening to someone else.

[Schyrsivochter]

Wat.

If disabling IPv6 on your network interface solves a problem with connecting to a server that doesn’t even have an AAAA DNS RR, then either there’s something very wrong with your network setup, or there’s something very wrong in the game’s code. Don’t think it’s the latter, though, seeing as this is working flawlessly on my machine, where IPv6 is always enabled.

 

Edited July 10, 2023 by Schyrsivochter

[auhmaan]

The only possible differences my network might have compared to others is open ports to certain servers and/or games, and Cloudflare/Google DNS, everything else is unchanged.

I could see outbound connections to an IPv6 that I assumed to be the SimRail servers, but wasn't getting any response reaching even the router, so either my ISP is/was having problems, or something else.

For now, since I don't have anything IPv6 specific that I need to use, disabling it on my machine does the job.