Solved Connection interrupted soon after opening a game

Hello,

I recently heard about this private realm and it has gotten me interested back into Diablo2 again (no bots!).
Installed it following the guides and everything worked pretty much right away first try, at least up to actually slaying monsters.

Very quickly after starting a game, the actions become unresponsive, I find black areas if I walk further, and eventually I get kicked with a "connection interrupted" message. Similar to a connection loss problem.

This happens pretty much systematically, although I haven't found any consistent reproduction steps. The delay before it happens seems quite random. Sometimes it happens right away (or rather, as soon as I start moving), and sometimes I can get 30s or more of play.
Note when I say "it happens", I'm talking about the moment actions are not having effect anymore (eg. can't select items in inventory). The "connection interrupted" message always appear around 30s later.

Notes on my machine :

• Windows 10 64 bits
  
• Was running COMODO security tools, which I uninstalled and now using Windows Defender and standard Firewall. No change with either.
• My internet connection should be fine. It's wired and very stable, I never had issues in multiplayer games, and ping 20-40 all around Europe.

Notes on my install :

• Before installing this I already had an official Diablo 2 copy, working, patched to 1.14d. The copy isn't literally "installed" on the computer as it was actually copied from a previous hdd. Diablo 2 doesn't appear in windows programs list. Also as a side note, it's not in Program Files either.
• I installed this realm by downloading the first link in the guide (some doc.google.com "Diablo II Lord of Destruction v1.13c (Portable).zip"), which I unzipped in another folder, then I applied the Realm patch. The install is clean and doesn't contain any third parties (neither does the official one btw).
• After talking with @Gix I also edited all .exe's properties to add XP(sp2) compatibility mode and run as administrator. But no change.
• Ran D2VidTst and tried both options (DirectDraw and Direct3D).

Here are a few interesting things I noticed :

• It seems not to happen as long as I don't move around. I was able to stand still, do random stuff in inventory, send messages in chat, etc. for several minutes without issue. Then, I start moving and boom.
• I am still able to play the official version fine, in closed bnet, for several hours. (Note that I had to switch around the gateways to do that but I figured it out)
• Sometimes a message pops up, sent by myself, containing gibberish (most likely binary data), either in chat or over my head. This message pops at the exact moment the connection breaks. The message does not always appear, and the content is always different. In a similar fashion I also got once a blue msg from battlenet saying "error: [] is not connected", which probably means the game tried to send a private message (with gibberish data to a gibberish recipient).
  
• The "GameGuard.log" contains similar gibberish when opened with standard notepad. I assume it could be unrelated if this "log" is actually meant to contain binary data.

I ran some tests in multiboxing to see what happens.
Let's define the following entities :

• Client A = my first running instance of the game, with character 1
• Client B = my second running instance of the game, with character 2
• Server A = character 1 as seen on the second instance
• Server B = character 2 as seen on the first instance

Here is what happens :

• I start moving around client A. Server A moves around too.
• At some point, Server A stops moving, even though I'm still moving around Client A. That is when the connection drops. Then I can't select stuff in inventory anymore, and if I run far away I see black areas.
• Now interesting part : if I move Client B around, Client A sees Server B moving.
• When Client A gets kicked, Client B sees a "timed out" message. If I close (or save&exit) Client A manually before kick, Client B also sees a "timed out" message immediately (no delay).

What I conclude is that for some reason, at some point, the client stops sending packets to server (or the sending thread crashes), but I can still receive server updates. Either that or the server stops accepting my packets.

Things I haven't tested yet (but plan on testing) :

• See if singleplayer has any issues
  
• Use wireshark to see if packets are actually going out after it bugs out
• Download client on the mega.nz mirror (Note that the second doc.google.com link returns 404)

Any further help is appreciated !

Thanks.

 

Wow, well, this should be definitely saved as a proper Troubleshooting post!

 

No doubt. Well done both of you.

 

Alright I got it to work yesterday eventually, after the hours we spent debugging this out.

I set up a VPN with one of my job's local server, which has Orange as ISP. The internet there is really shitty, and I had massive lags with 200-400 ping, and yet I didn't get a single disconnect in more than 1 hour of play.
So the problem definitely comes from my ISP (Free SAS), even though I can ping d2.europebattle.net at 20ms consistently. There must be something my ISP doesn't like about D2 or GameGuard protocol.

About the fact I can stay longer while standing still : I suspect it has to do with client not sending many packets while standing still. Doing stuff like moving inventory items and sending chat messages, is extremely slow compared to sending movement updates. The scarcity of packets sent makes it less likely to "crash".

About the binary message sent sometimes : My personnal theory is that an ISP routing issue causes a badly handled exception on the client, which causes code to randomly jump somewhere and, for example, send a chat message, or an overhead message, or a private message, or an invite, using whatever data in the stack at this moment. Then the sending thread is in a bad state and cannot send anymore, while another thread can still receive server updates. That is a long shot because I know nothing about how the game works, but it's my only theory at the moment.

Anyways thanks for the help. If you have more ideas I'm here to try. Or if you know a good (free) VPN I'd be grateful as well.
Meanwhile I'm gonna play like this until I find out a better one, or until my ISP fixes the issue on its own, like it might have done in the other posts you mentioned.

 

Whew, after the router reset it seems to be working now!
I think it also installed a firmware update during the reboot, because I saw it reboot twice.

Anyways, thanks for all the help!!