[Glave]

Can anyone provide a solution other than switching ISP? Im having the same issue but its ONLY for L4D2. My Ark, Minecraft, Project zomboid and Valheim servers all work and are joinable by people outside my network.
Trying for force an IP just causes the server to crash on startup so im pretty stumped at this point

[Loll10T]

Originally Posted by Loll10T I'll edit this if I find anything different on my friend's output.

Not an edit, but here's my friends output when typing 'status':

hostname: Left 4 Dead 2
version : 2.2.2.6 8776 insecure  (unknown)
udp/ip  : XXX.XXX.XXX.XXX:27015 [ public XXX.XXX.XXX.XXX:27015 ]
os      : Windows Dedicated
map     : c2m1_highway
players : 0 humans, 0 bots (4 max) (hibernating) (unreserved)

# userid name uniqueid connected ping loss state rate adr
#end

Originally Posted by Bacardi Does it make any difference, if you disable hibernation? sm_cvar sv_hibernate_when_empty 0

No good. I'm still unable to connect to my friend's server.
It's worth reminding that they don't have CG-NAT, and that they have a public IP.