If both of you are using the same version, same pakset, and you are forwarding ports and managed to get the game in your list, then I don't know what's wrong, that's everything you need to do.

I would need you/your friend to send me some logs to know what's happening.

But maybe try the new release first, just in case it solves this.

I'm kind of having the same problem, @Roboron... First I went to simuforum for posting it but I cannot remember my password there and it's been a couple days since I requested a pw resend (still no message from simuforum in my inbox though).

I don't know if it's the same version or problem OP is having, but here goes:

Simutrans 124, Pak128 = both latest from the official website
Linux Mint OS, 21.3 Cinnamon
Default game port allowed and opened (and tested in Terminal) in both the modem and the OS

launch command
./simutrans -log 1 -debug 2 -server 13353 -announce -server_dns [my IP] -server_name "Mapa-Mundi" -load [savegame-name.sve]

The game appears in http://servers.simutrans.org/ (not now though, I halted it atm) but no player can connect to the session - these are the error messages I got from two players (they have all installed the same version as the host's):

"Server did not respond!"
"An operation was attempted on something that is not a socket"

The server shows up in the client's serverlist only after clicking 'Show Mismatched'

I really am puzzled... I often host some couple games from time to time and by far Simutrans was always the easiest game for hosting - and now I'm not sure whether it's a new version issue or just dumbness from my side

EDIT¹
netstat -tunlp shows the game's
tcp6 Local Address and Foreign Address as ":::13353"
tcp Local Adress and FOreign Address as "0.0.0.0:"
no udp/udp6

EDIT²
Server Terminal output while hosting:

Simutrans version 124.0 from May 4 2024 r11164 hash 0x0c9305b
Warning: simwin.cc themes_init(): Can't read themes from themes.tab
Warning: dr_load_sample: Could not load wav: Couldn't open /home/edwin/simutrans_124/pak128/sound/desert.wav
Warning: sound_desc_t::get_sound_id(): Sound "desert.wav" not found
Warning: dr_load_sample: Could not load wav: Couldn't open /home/edwin/simutrans_124/pak128/sound/mediterran.wav
Warning: sound_desc_t::get_sound_id(): Sound "mediterran.wav" not found
Warning: dr_load_sample: Could not load wav: Couldn't open /home/edwin/simutrans_124/pak128/sound/temperate.wav
Warning: sound_desc_t::get_sound_id(): Sound "temperate.wav" not found
Warning: dr_load_sample: Could not load wav: Couldn't open /home/edwin/simutrans_124/pak128/sound/tundra.wav
Warning: sound_desc_t::get_sound_id(): Sound "tundra.wav" not found
Warning: dr_load_sample: Could not load wav: Couldn't open /home/edwin/simutrans_124/pak128/sound/rocky.wav
Warning: sound_desc_t::get_sound_id(): Sound "rocky.wav" not found
Warning: cbuffer_t::check_format_strings: Broken master string '<em>%C</em> - %s<br>
': Format specifier 0 contains invalid characters.
Warning: cbuffer_t::check_format_strings: Repaired broken translation string 'Vuajittai vähi' of 'Speedbonus
road %i km/h, rail %i km/h
ships %i km/h, planes %i km/h.'.
Warning: cbuffer_t::check_format_strings: Broken master string '<em>%C</em> - %s<br>
': Format specifier 0 contains invalid characters.
Warning: translator::load_files_from_folder(): /home/edwin/simutrans_124/pak128/text/ce.tab no language 'pak'
Warning: skinverwaltung_t::register_desc(): Spurious object 'Builder' loaded (will not be referenced anyway)!
Warning: simwin.cc themes_init(): Can't read themes from themes.tab
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: FluidSynth: Failed to set thread to high priority
Warning: midi_init(): can't open file '/home/edwin/simutrans_124/pak128/music/music.tab' for reading.
Warning: midi_init(): can't open file '/home/edwin/simutrans/music/music.tab' for reading.
Warning: karte_t::load: Disconnecting all clients
Warning: karte_t::load(): loaded savegame from 0/1930, next month=16777216, ticks=4521156 (per month=1<<24)
Warning: karte_t::interactive: Server lagging by 1462 ms (22 steps)
Warning: nwc_tool_t::clone: send sync_steps=1 tool_id=TOOL_ADD_MESSAGE work

If you can tell me what your e-mail is, I can reset your password. Unfortunately, the forum is unable to send e-mails to some addresses (gmail).

Otherwise, I will forward this report to the forum later.

Originally posted by Roboron:

If you can tell me what your e-mail is, I can reset your password. Unfortunately, the forum is unable to send e-mails to some addresses (gmail).

Otherwise, I will forward this report to the forum later.

Thanks, Roboron! Yes, it's a Gmail account... it's diego.ramires.usp@gmail.com

Taking a look at the log you shared there are no attempts to connect to your server! Is that part of the log missing? Otherwise, it would suggest that your server is not accesible by the clients that tried to connect to it - check your network settings.

Originally posted by Roboron:

Taking a look at the log you shared there are no attempts to connect to your server! Is that part of the log missing? Otherwise, it would suggest that your server is not accesible by the clients that tried to connect to it - check your network settings.

That log is from the time I opened the server but at that time no other client was trying to log in - since then the other players weren't available to try and log in again so I could check up the log for logging attempt entries. I'm still waiting for posting it in the forum because first I want some client to send me their log too

Originally posted by Roboron:

Taking a look at the log you shared there are no attempts to connect to your server! Is that part of the log missing? Otherwise, it would suggest that your server is not accesible by the clients that tried to connect to it - check your network settings.

UPDATE: Seems that it was my own dumbness lol... my native Linux firewall was enabled and after upgrading to the latest Mint my firewall exceptions were erased. Fixed by adding the port to the firewall. Again, thank you for all your support, Roboron! :)

Glad it was your dumbness and not Simutrans' :D

You are welcome!

(Thanks Steam for not telling me about replies until today :( )

So I did update and tried again with another friend using pak128 and connecting from either the list or directly via IP gave the same error "An operation was attempted on something that is not a socket".

I have port forwarded on windows, my antivirus and my actual modem/router combo with no change. The server does show up in the listing like it did before. Basically, the only thing that has changed is the error message, and the version we are both on (that being the most up-to-date Steam version).

If you would direct me on where to find the logs, I'll try and get them for you.

In Steam launch parameters, add the following "%command% -debug 3 -log". Then, a "simu.log" file will appear in your user Simutrans folder. Make sure that you have a friend attemtimpg to connect to your server.

But this is most probably something wrong with your network configuration. Even if you appear in the list, that only means you can connect to the listing server, not that others can connect to you.

Something somewhere may be blocking port 13353. Share a screenshot of your router configuration to see if it is properly forwarded.

You can also try to set the "server_dns" setting to your own IP if you haven't already.

Originally posted by AtSburbsEnd:

(Thanks Steam for not telling me about replies until today :( )

So I did update and tried again with another friend using pak128 and connecting from either the list or directly via IP gave the same error "An operation was attempted on something that is not a socket".

I have port forwarded on windows, my antivirus and my actual modem/router combo with no change. The server does show up in the listing like it did before. Basically, the only thing that has changed is the error message, and the version we are both on (that being the most up-to-date Steam version).

If you would direct me on where to find the logs, I'll try and get them for you.

Afaik all players - not only server - have to have the port forwarded, don't they?

Only the server host need to have the port forwarded.