Ondrej Žilinec – IT Blog

I didn’t know that it’s possible in Windows TCP/IP stack make port forwarding. I knew it’s possible in Linux using iptables. In windows we have powerful tool called netsh.

Let’s have a example. Some service is listening on port TCP/10000. If I want to make this service listen on other port than TCP/10000 and there is no configuration to change I will use netsh to make it happen. Let’s look at listening ports on TCP/10000 and TCP/20000:

We can see there is no port listening on TCP/20000. Let’s make a magic and run command:

netsh interface portproxy add v4tov4 listenport=20000 listenaddress=0.0.0.0 connectport=10000 connectaddress=192.168.100.118

You cannot use loopback or 0.0.0.0 in connectaddress parameter. You can even use remote server IP address in connectaddress parameter.

Let’s look at netstat commands:

If your command doesn’t work, please, check if service called IP Helper is Running.

To see all configuration of portproxy settings just run following command:

netsh interface portproxy dump

To delete rule just run following command:

netsh interface portproxy delete v4tov4 listenport=20000 listenaddress=0.0.0.0

And that’s all folks,

Once upon the time I had problem with Windows Update. All updates got downloaded and installed. When user click on button Restart Windows got error 0x80070005.

After couple minutes of debugging with Process Monitor I found out that process called explorer.exe had problem with accessing directory C:\Windows\System32\Tasks. That means that if you click on button Restart in Windows Update, Windows doesn’t just restart system. It creates Scheduled Task to reboot. Weird, but it does it this way.

So I have created GPO with security settings for directory C:\Windows\System32\Tasks and allow BUILTIN\Users have Modify rights to this directory.

And that’s the way we make it 🙂