University Computer Help Desk

Opening firewall ports for the Cisco VPN Client

To use the Cisco VPN Client with a firewall, you must open three firewall ports. Failure to do so may result in timeout and disconnect problems with the Cisco VPN Client.

Firewall Ports

To use the Cisco VPN Client, the following network ports must be opened in your firewall software:

  • 500 UDP
  • 4500 UDP
  • 10000 UDP

When you install the Cisco VPN Client, it automatically opens these ports in the Windows firewall. If you have another software firewall installed on your computer, you will need to manually open these ports.

Opening Windows Firewall Ports

The instructions below describe how to open the necessary ports in the Windows firewall. These ports are automatically opened in the Windows firewall when you install Cisco VPN Client. If you have problems using the Cisco VPN Client due to timeout or disconnect issues, follow these instructions to confirm your Windows firewall settings.

  1. Follow the instructions for your version of Windows:
    • Windows XP
      Click Start > Control Panel > Network and Internet Connections > Windows Firewall.
      - OR -
      Click Start > Control Panel > Windows Firewall.
    • Windows Vista
      Click Start > Control Panel > Allow a program through Windows Firewall
      - OR -
      Click Start > Control Panel > Windows Firewall > Change Settings
  2. Click the Exceptions tab.
  3. Click Add Port…
  4. In the Name: box, type VPN-(port #)-UDP. For example: VPN-500-UDP
  5. In the Port number: box, type the port number you are adding. For example: 500
  6. Select UDP.
  7. Click OK.

Repeat steps 3 - 7 until you have added all three ports: 500 UDP, 4500 UDP, and 10000 UDP.