[sedano132]

A method to connect to your dedicated server L4D2 in the same local net through the lobby when you have trouble to reach it.(May be CSGO too?)

Say thanks to the corona virus.
It only took 10 years but finaly I found a method to connect to your server through the lobby.
Worked 100% of the times that I have tested, replicated the bug every times.
It have a long explanation that lies in a bug of the server code that I think no one has ever had an iteresting in corretting. The mistake born when the client that try to connect to the server has the same external ip of the server and the server cannot handle this.
My fault,for many time, was the attempt to modify the client ip, but the solution is to modify the server ip (with a wrong ip)with a simple setting that, strangely , do not affect the server functionality.
So simply put in the startup command line of the server the setting:
+net_public_adr xxx.xxx.xxx.xxx
Put instead of xxx.xxx.xxx.xxx a fake ip (exemple 151.151.151.151 that problaby will be not your real ip....or use another.....) and this will trick the server that will think that xxx.xxx.xxx.xxx is his external ip and it is done. Now you may connect to the server in whatever method you prefere because the client ip(real) do not corresponds with the server ip(fake) and the dummy server accept the client's connection that in reality have the same ip.

Additionaly, but probably not necessary, I prefere also to put in the same line the setting for the internal ip +ip xxx.xxx.xxx.xxx that is (surprise!) the internal server ip.....(to many word to explaine why but you need to know that if it is the right ip however it do not hurts).

The simple way to do that is to put this setting in the start up command line (Tutorial section 3.5)like this [...YourAnyFolder\serverl4d2\left4dead2\srcds. exe -console -game left4dead2 +map c1m4_atrium +mp_gamemode "survival" +net_public_adr xxx.xxx.xxx.xxx +ip xxx.xxx.xxx.xxx +port 27015]

You also may set this parameters in the server console on the fly.

If I will find people interested in this I will be more detailed in my explanations.

May be that this might work also with the other games that use the same server platform (may be CSGO too?). Let me know.
Thanks.