crossplay between steam and GOG possible?

[JolyJew СлаваУкраине]

my friend got the game on GoG, but there is now a sale on steam. will i be able to play the game with him if we own it on different store platfroms?
or should i just buy it from GoG?

[Ettanin]

You can, though make sure you or your friend has a dedicated (also known as public) IPv4 address. Static or dynamic doesn't matter.

The host has to forward TCP ports 23243, 23244, 23245, 23246, 23247, 23248, 23249, 23250, 23251, 23252, 23253, 23254, 23255, 23256, 23257, 23258, 23259, 23260, 23261 and 23262 or at least have UPnP enabled. This is not possible with a connection that uses Dual Stack Lite or CGNAT.

Steam-to-Steam doesn't need to do that because Steam Datagram Relay will be used in case of missing forwards, CGNAT or Dual Stack Lite. Steam-to-GOG however cannot use Steam Datagram Relay and hence needs the forwards for a direct connection.

If both of you are on limited (CGNAT or Dual Stack Lite) connections, you both are better off getting the Steam version and should ditch the version on GOG. The saves are cross-platform compatible.

[.decay]

ALL OF THAT IS UN NECCESARY JUST SEND YOUR DIRECT LINK TO THEM AND THEY CAN JOIN

[JolyJew СлаваУкраине]

So which one is it? There arevonly 2 opinions and they completely contradict each other

[Ettanin]

Originally posted by JolyJew СлаваУкраине:

So which one is it? There arevonly 2 opinions and they completely contradict each other

mine.

.decay is a troll

See also here: https://steamcommunity.com/app/435150/discussions/0/1290691308575341727/

If you cannot do this (either by lack of knowledge or for network technical reasons), you and your friend both better get the Steam version and Steam will take care of it for you. As i said, Steam will create a VPN-like connection for you and your friend if you both play via Steam and port forwards weren't configured properly or wouldn't work.

[Razorblade]

Originally posted by Ettanin:

mine.

.decay is a troll

See also here: https://steamcommunity.com/app/435150/discussions/0/1290691308575341727/

If you cannot do this (either by lack of knowledge or for network technical reasons), you and your friend both better get the Steam version and Steam will take care of it for you. As i said, Steam will create a VPN-like connection for you and your friend if you both play via Steam and port forwards weren't configured properly or wouldn't work.

The Larian staff member in the comments of the post you linked pretty much agrees with .decay. Unless your network is unusually restrictive, sending your friend the direct connect code is all you need; no port-forwarding or VPNs needed.

Moreover, there are dozens of examples online of direct connection working just fine out-of-the-box:
https://www.gog.com/forum/divinity_original_sin_2/gogsteam_crossplay_1
https://www.reddit.com/r/DivinityOriginalSin/comments/8os90n/steam_and_gog_crossplay_what_restrictions/
https://steamcommunity.com/app/435150/discussions/0/1738883005313143189/
https://store.steampowered.com/news/app/435150/view/5154889050469034700?l=polish

It's hardly trolling to give OP the simplified version of the information, rather than a lecture on the nuances of port-forwarding. Chances are, GoG-Steam crossplay will work just fine for them. The post's question was "Can Steam and GoG play together." The answer is a simple "Yes."

However, you jumped immediately to troubleshooting a problem that OP doesn't have, which now probably has them convinced they need a network-engineering degree to play this game. Troubleshooting is best saved for if someone has an issue; not in case they have an issue. Too much unnecessary information distracts from the actual pertinent information, which is that Steam-GoG crossplay should work with minimal effort required.

TL;DR (For OP): GoG and Steam crossplay works fine and is relatively simple; you just have to enable Direct Connections in your lobby settings and send your friend the code provided, since the server browser can only see people playing on the same platform. It's an incredibly easy process.

[Ettanin]

Originally posted by Razorblade:

It's hardly trolling to give OP the simplified version of the information, rather than a lecture on the nuances of port-forwarding. Chances are, GoG-Steam crossplay will work just fine for them. The post's question was "Can Steam and GoG play together." The answer is a simple "Yes."

I wanted to help them with the observations of my personal coop gameplay. Steam-to-GOG does not use any tunneling services out of the box and because dedicated IPv4 addresses are no longer given out as the norm, direct connection or using the server alias method will not work. Both port forwards and UPnP REQUIRE a dedicated static or dynamic IPv4 (both commonly known as a "public" IPv4) address which most users no longer have as most ISPs will use a CGNAT or Dual Stack Lite.

THIS fact is missing in Larian's answer and all the answers you were linking.

Steam-to-Steam gets around this issue by using Steam Datagram Relay, which is a Steam-exclusive feature.

So, while in essence their answer may be true, the TONE they brought it about is in a trollful manner.

The answer is, considering the internet technology used commonly nowadays, a "Yes, but you will likely have issues."