I have heard and read that ppl have trouble getting into the Kingpin servers to play online when using the GoG.com version of KP.
I have just installed the GoG version on a PC and attempted to join a server.
For servers not running the monkey mod anti cheat mod I was able to join without any problems.
But when I joined a serer running the monkey mod I got kicked for using an invalid exe.
All I did to fix this issue was to reinstall the v1.21 patch and now I can join all the servers runing the monkey mod.
"""Please note, if you repatch the game, when you try to start the single player game it will ask for the cd to be loaded. To get around this I installed the nocd patch which you can get from here - http://downloads.kingpinforever.com/kp121cr.zip ***
You can get both the v1.21 patch and the monkey mod client in the kpstarter pack here -
http://downloads.kingpinforever.com/kp_starter_pack.zip
We also have a guide on how to patch the game and install the monkey mod client here - http://www.kingpinforever.com/kp101/
There are around 20 kingpin servers running currently and the best way to join them is probably to use GameSpy Lite. It usually is inlcuded with KP but isn't included with the GoG version. However we host an updated version of it at KP4Ever - http://downloads.kingpinforever.com/Kingpingspylite.Kingpin.Forever.Update.Final.zip
The install guide listed above explains how to set up GS Lite with the monkey mod so you can use it to join all the KP servers.
If anyone is having problems joining servers running the monkey mod and wants to try this fix listed here plz respond whether it worked for you too.
Thanks,
Mr D

EDIT//
Multiplayer is now working with gamespy. problem solved.

GameRanger works just as well.

I just downloaded Kingpin from GOG and also downloaded the GameSpy light mentioned above. When I have tried to download MonkeyMod, my McAfee antivirus is saying that the program contains a Trojan and won't allow me to install it. From what I was reading, I thought that GOG Kingpin programs might be excluded from having to use Monkey Mod but when I try and join a server, I am getting the following error message: I/O Error 123. Any ideas about what I might be doing wrong?

thanks for the tip. also your avatar reminded me of one of my favorite games back then, which i definitely wanna see on gog. i remember that i had to use a hex editor to get blood into the game, because they censored it over here. setting "blood=0" to "blood=1".kinda tricky, isn´t it?^^

Heh, yeah. That's how censorship worked in games back in the day! A simple numeric value change.

Anyone know the multiplayer status of Kingpin now? I know the Gamespy servers got shutdown and I'm wondering if the community has got a solution for it.

Hi,

There is another server browser you can use which includes Kingpin servers and that one is QTracker - http://www.qtracker.com/

Gamespylite, which comes with Kingpin, was working up until a few days ago but then stopped working *sigh*.
[M] already came up with a workaround for this though:-

It is possible to have the Kingpin Servers show up in Kingpinspy again, using the qtracker master server as opposed to gamespy.

On a windows computer, add the following 2 lines to the file

C:\windows\system32\drivers\etc\hosts

65.112.87.186 master.gamespy.com

65.112.87.186 master0.gamespy.com


You will now be able to see the servers in Kingpinspy/Gamespylite again.

I used notepad for this task and had to run it as an administrator (right click on notepad and run administrator). Now all Kingpin servers are showing up in GSLite again :)

The Kingpin server browser Gamespy Lite (which comes with most versions of Kingpin) has been fixed/updated and is working again. Even the chat works now :)

Just extract the kingpinspylite.exe file to your Kingpin/Gamespy folder (it will overwrite the original one so make a backup of that before you overwrite it if you want to).

If you don't have a Kingpin/Gamespy folder just create one.

http://download.kingpin.info/index.php?dir=kingpin/patches/unofficial/gamespy/&file=gamespy_lite_kingpin.zip

For new players who want to play online here is a good video tutorial on the basics of playing Bagman.
https://www.youtube.com/watch?v=O9Lf0zuc3u4