ANAL-JUSTICE

@daantje050: this was very helpfully , big thx. I was able to solve the problem too.

But I did a different ways and tries and found out, that the ".. -external provider" connection message whil connection appears if I didn't have the local ip used in options for lan & online.

In options.ini these are the important lines:

...
FirewallBehavior = 0
FirewallNeedToRefresh = FALSE
FirewallPortAllocationDelta = 0
FirewallPortOverride = 0
GameSpyIPAddress = 192.168.178.20 (!!! must be the address of your network-adapter connected to the rooter !!!)
...
IPAddress = 192.168.178.20 (!!!same here !!!)
...

sometimes it takes the online ip of the provider after saving in options or refreshing NAT.

I tried the port 16000 override too, but it makes no different.
But I also delete forwarded ports from cnc and don't use them a.t.m. (TCP: 80; 6667; 28910; 29900; 29920.
UDP: 4321; 27900.) and it works fine

testet 1v1, 1v1v1v1v1v1 and 2v2v2 ... so ... maybe the old ports are not needed anyway,,,

I didnt have any port forwarded at my rooter NOW !


EDIT:

I made several games and the message appears again:

now i switched back to online ip with this in config

...

FirewallBehavior = 0
FirewallNeedToRefresh = FALSE
FirewallPortAllocationDelta = 0
FirewallPortOverride = 0
GameSpyIPAddress = 0.0.0.0
...
IPAddress = 0.0.0.0

it works again, but now i am very confused ... but i will reply if i got a final state.
 

Same Problem here, nothing changed and now I get the "Establishing Connection with External ISP" too.

- Windows 7-64 (sp2)
- static IP in LAN to rooter, (192.168.178.20 IPv4)
- Ports are fowarded in NAT for this ip (TCP: 80; 6667; 28910; 29900; 29920 UDP: 4321; 27900)
- windows Firewall is off,

I can log in to generals ZH, see people in Lobby, but if I create or join a game, I get this Connection-Message. I am sure that there wasn't "Establishing Connection with External ISP "-message in past while connecting, it was only "Establishing Connection with ISP".
Why is my ISP now listed as "external"  while connecting. And how can it be fixed?

(I also tried another rooter, but same issue...)

C:\Users\machine>ping peerchat.server.cnc-online.net

Ping wird ausgeführt für ripper.icetex-hosting.net [185.17.144.132] mit 32 Bytes
 Daten:
Antwort von 185.17.144.132: Bytes=32 Zeit=19ms TTL=55
Antwort von 185.17.144.132: Bytes=32 Zeit=20ms TTL=55
Antwort von 185.17.144.132: Bytes=32 Zeit=20ms TTL=55
Antwort von 185.17.144.132: Bytes=32 Zeit=19ms TTL=55

Ping-Statistik für 185.17.144.132:
    Pakete: Gesendet = 4, Empfangen = 4, Verloren = 0
    (0% Verlust),
Ca. Zeitangaben in Millisek.:
    Minimum = 19ms, Maximum = 20ms, Mittelwert = 19ms