So long as I have the Windows Firewall turned off, internet passthrough works perfectly. Running without a firewall is not feasible for me so I'm trying to find out which app or port the passthrough uses. I've created an exception for HTC Sync but this clearly isn't what manages the connection.

Can anyone shed any light on this?


Complete tutorial can be found here

You can try to add and exemption to the port that the PC assigns to the HTC application to connect the the internet.

How to find what port the HTC devices uses on the pc:

  1. Power off the firewall.
  2. Connect your HTC device to the internet using your pc.
  3. Open task manager and look for the HTC application process.
  4. Write down the PID.
  5. Open command prompt.
  6. type in netstat -ano.
  7. it will give you a list of open ports on your pc.
  8. Look for the HTC application port by matching the PID.

How to find the PID of the process in Task manager

  1. Open Task Manager.
  2. Click on View.
  3. Click on Select Columns.
  4. Check mark PID (process Identifier).
  5. Click OK.
  6. Should display the PID of the processes.

How to add a exemption to the Windows 7 Firewall.

  1. Open the Control Panel (All Items View).
  2. Click on the Windows Firewall icon.
  3. Click on the Allow a program through Windows Firewall link in the left blue pane
  4. Click on the Change Settings button NOTE: If the Change Settings button is grayed out, then it has already been clicked on. You can proceed to either step 5, 6, or 7 for what you would like to do.
  5. To Allow or Unallow an Existing Exception

    • On the left side, check the program exception Name box to allow, or uncheck to unallow through Windows Firewall.

    • If you allowed the program exception, then check (allow) or uncheck (unallow) the box for each Private or Public network location you want the program to have access through Windows Firewall.

  6. To Add a Program Exception

    • Click on the Allow another program button.
    • If the Program is Listed - Click on the program to highlight it. Skip the next step
    • If the Program is Not Listed - Click on the Browse button. Navigate to the program's exe file location, usually in a C:\Program Files folder, and click on the program's exe file to select (highlight) it and click on the Open button.
    • Click on the Add button.
    • Do step 5 to allow to unallow this program exception.
  • I've tried this - can't see the entries or PIDs for HTC apps in the listing...
    – 5arx
    Sep 28 '11 at 15:24
  • netstat -ano brings up the ports currently on used on your pc. there should be a port in there with the same PID as the HTC app. Remember you need to find the PID for the HTC App in Task Manager.
    – bbatman
    Sep 28 '11 at 15:34
  • That's what I can't find - any chance you could post a screenshot?
    – 5arx
    Sep 28 '11 at 15:39
  • ok so you can't find the PID. I will try to get a screenshot for you in a couple of hours. I am a work :)
    – bbatman
    Sep 28 '11 at 16:28
  • 1
    Updated the Answer to include of how to add the PID column to Task Manager.
    – bbatman
    Sep 28 '11 at 17:54

This is what makes the outbound connection for HTC:

C:\Program Files (x86)\HTC\Internet Pass-Through\htcnat.exe


C:\Program Files\HTC\Internet Pass-Through\htcnat.exe


Just in case other people look here and want a quick answer, I get HTC sync working by opening ports 2002, 49167, 12000, 24801, 49168, 139 and 135.

  • Ummm how do you "open ports"?
    – Ivan Wang
    Sep 9 '14 at 12:27
  • @ivan, OK I mean "allow connection" through this port, as described in bbatman's answer. Depends on the firewall you have, I was using Eset, so went as per vikas's answer. Sep 10 '14 at 9:04
  • Thanks. I have solved the question by restarting the PC. I know...
    – Ivan Wang
    Sep 10 '14 at 14:21

FIREWALL is the culprit... Try this, it may work 4 u too...

I use ESET on WinXP..and have my windows firewall disabled. You can go through this and possibly do the analogy on whatever OS and antivirus you have.

  1. In network connections you have to change the properties of the connection i.e. the one used by your phone not the actual system internet connection. For avoiding confusion, disconnect your phone, now go to network connections page, now connect the phone in internet pass through mode. A new connection must appear on the network connections page. That is your phone connection.

    Right click on it and open properties:

    1. in general tab un-tick the Eset Personal Firewall
    2. now go to tab advanced->firewall settings-> mark it off if it is on.
  2. The Internet pass through is maintained by htcnat.exe on your system. You can see it running in Task Manager.

    Add it as an exclusion in your firewall (You can find htcnat.exe in "C:\Program Files\HTC\Internet Pass-Through)

If you are using ESET, you have to additionally exclude the app htcnat.exe in protocol filtering which is found under "antivirus and antispyware" in advanced settings In protocol filtering, htcnat must be checked in excluded applications.

This protocol filtering step was the one which was stopping me from using the internet pass through. Even disabling the firewall did not work for me. Now all is well.

All you need is to have the NDIS driver installed. Then make sure the firewall is not interfering with the connection. Go through all the settings.

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