TCPMUX server outbound dynamic ports

[Liverdog]

Don or other advanced users:

I have a very restrictive VPN client, which is also the only way I can use the remote client back to the WIN500 server. On the VPN client I can choose any port, but inbound and outbound must be known before the connection is established and be static. However, running netstat on the machine running the TCPMUX server I see that the outbound port back to the client is dynamic. This is a big problem since I need to know the return (outbound) port before I establish the VPN. I think this is being used for the audio portion of the remote client. Can you verify this?

In my netstat I see inbound on 26755, but outbound is dynamic in the 27xx range.

Is there a way to configure the TCPMUX proxy so that the same (static) port is used outbound?

BTW, I can connect to the server using the remote client through the VPN it just doesn't have any audio. That's why I think the dynamic port is the audio stream.

Thanks

 

[DonS]

All data to the client is on the same socket, meaning it's all on one outbound port from TCPMux.

If you're getting LCD and status updates in the client app, you should also be getting audio data. You can verify that you're getting all of the data by looking at the "bps" field in the client app: it should hit a steady state of ~18kbps.

 

[Liverdog]

Thanks for responding Don. I do have LCD updates and can control the scanner, but have no audio. The data rate is low. It is < 3kbps as displayed on the client. I don't think this is a bandwidth issue as I can transfer other data at ~700kbps. Can you think of any other diagnostics? I am still stuck on why there is a random socket that opens up on the server side opposite the inbound port. It disappears when I close the client and then reappears when I reopen it (with a new port).

If you're familiar with Teamspeak, this app acts the same way and is also unusable for me since the outbound socket is random.

[Edit: I eliminated TCPMUX from the equation. I am now going direct to the server over the native 8086 through the VPN, but I experience the same behavior. Each time I connect and then exit I generate a new pair of sockets in the netstat output. The new outbound socket seems to be incremented by 2 or 3 from the previous one and the old ones from previous connects are sitting in the "TIME_WAIT" state.]

 

[smason]

I think that's the way TCP works, though it's been a while...

If I make a web connection to Radioreference.com, I request it on port 80 (destination port), but the source port is a random dynamic port. When Radioreference.com sends me back the page I requested, it's source port is 80, and destination is whatever source port my request packet used.

I doubt that this is configurable in a user program, as far as I know, the TCP/IP stack takes care of all this.

 

[Liverdog]

Hey Don. I am guessing that you don't pass audio on localhost (127.0.0.1), correct?

I bet that's the issue. My remote client (through the VPN) connects as if it were local (i.e. localhost). I notice that when I run the remote client locally (on the server itself) the bandwidth is also low <3kbps and the mute audio does nothing. Could this be the issue? I need to work out of the 127.0.0.1 on the remote client?

 

[DonS]

Audio, status, LCD, and "log" data are all on the same socket/IP/port. If Win500 is sending any one of them, it's sending them all.

If you're not getting audio even when running the client on the same PC as the server, it sounds like Win500 itself isn't getting any audio data. Have you tried changing the audio input device? By changing the setting in Win500's Configuration -> Audio Input Device menu and/or by making sure the Windows Mixer actually has enabled the input "port" you're using?

 

[Liverdog]

Hi Don. Again thanks for the support. I restarted WIN500 at the server and the audio stream came back with the data rates where they should be. I don't know what happened. No other audio settings were changed. Thanks.