Factorio Forums

During a long stretch of testing with some help from #factorio, there seems to be an issue with more then two players connecting.
Only recently have I been keeping logs and saves, so as I continue to troubleshoot I will post what I have.

The normal behavior is that the second player will connect normally, and then when the third player connects, they either immediately drop, or will download the entire map and the third player be stuck at a black screen. When this happens, players previously in game usually get the darken screen and pause type behavior. Very rarely, the connection will work, but will show similar trouble with a 4th, and desync's are generally unrecoverable.

"Chaining" connections from one player to the next, and not having everyone connect to the initial host, seems to help the issue somewhat, but still not regularly enough to be suggested as a workaround.

Tested conditions:
Fully stock, no mods.
Same issue with or without biters spawned.
Fresh saves tested.
Old saves tested.
Locations (for the different players): Tested US to US, AUS to US, GER to US, No change in behavior.
Updated install from 11.5 (will test fresh 11.6 when able)


To follow: Several uploads of saves and logs from the most recent testing attempt, using both 11.5 and 11.6 saves on 11.6

Tested saves and logs

https://www.dropbox.com/sh/m7ekr69nmt6k ... D0lma?dl=0

MPtesting was the initial testbed save, generated in 11.5.

Current log 1st was these tests:
{1} loading an 11.5 save, first player connected and then locked into a desync loop.

MPtesting2 was generated in 11.6.
1st attempt: After the third player attempted to connect, the host froze when the third player attempted to connect.
2nd attempt: After the second player connected, all subsequent (3) connections were dropped upon connection.

MPtesting 3 was saved while a desync loop was occuring. Log 2nd was taken during this as well.

I have same issue with 11.4-11.5 versions. After tests with my frends we discovered stable relation between this bug and lobby latency settings. If I set it to 99ms+, then third player has black screen after connect. If this setting is less then 99ms, everything is all right. This behaviour retains both on my home computer and dedicated server in another city.

As a follow up to Ciiol's suggestion, I'll add the following information.

The initial testing was tested at 199ms, the normal value I personally use.
Followup testing with different latencies was tested, with logs and saves located at the dropbox previously linked.

First, a new map (mplattest.zip) was generated in 11.6.
Loaded in MP at 83ms latency.
Player Two connects, desyncs immediately, and re downloads map successfully.
Third player connected, players 1 and 2 frozen and player 3 is blacked out.
Saved mplattestres.zip and generated currentlat83.log
Restarted factorio.
Reloaded mplattestres.zip at 66 ms
Player two connects normally.
Player three connected, players 1 and 2 frozen, player 3 blacked out.
Generated currentlat63.log

Both players involved had about a 80 ms ping to me.
All players running the x64 version of factorio.

Upon further suggestion from Nemoder, we tested a few things.

Loading mplattest.zip, 99ms latency.
Players 1, 2, and 3 all have windows x64.
Players 1 and 2 connect, 3 connects and immediately drops.
(This excludes any cross-os issues, as tested)

I then had a idea about the how the players generate, and had player 2 connect, then drop, had player 3 connect, then drop, and had player 2 and 3 reconnect, and everything worked fine. I ran out of testers to do further testing.

If no new players connect right after each other, it seems everything works out alright, as long as the previous players already have the data generated for them. That might explain why some don't notice it unless you generate a completely new save, since player data is already generated for previous players.

I also have the problem with 3rd player connecting, where any 2 players can play together, but when the third joins the described problem occurs.

For reference: https://forums.factorio.com/forum/vie ... f=7&t=7384

It should work in 0.11.8 now.

Hurray! Thanks folks, for working on it! if i have any continuing problems, i'll be sure to let you guys know.