ARCHIVED: While attempting to connect to the IU VPN server via IPsec, why do I get a message that the server is not responding or is unable to complete a connection?

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For off-campus connections to the IU network, use the recommended SSL VPN.

Provided you have already completed the instructions for your operating system, your VPN connection problems are probably caused by a local firewall or the use of private addressing through a router or Internet-connection-sharing software.


If you are running a firewall, try disabling it temporarily. In Windows, most of these software packages will add an icon to the notification area at the bottom right corner of your screen, next to the clock. Usually you can use this icon to enable or disable the firewall. If disabling the firewall allows use of the VPN, you should be able to add the name of the VPN server (Indiana University Bloomington:; IUPUI: to your firewall's allowed hosts list, re-enable the firewall, and successfully connect to the IU VPN.

Note: Norton Internet Security and Norton Personal Firewall frequently cause problems for Windows computers trying to connect to IU VPN.

For recommendations about antivirus software, see Recommended antivirus software at IU.

Private addressing

Private IP addresses (or reserved IP addresses) are most frequently used within a local, private network. Computers with private IP addresses that need to access the Internet first go through the process of Network Address Translation (NAT). In many broadband situations, NAT is performed by a DSL router, cable router, proxy server, or Internet-connection-sharing software.

Such solutions allow multiple computers to access the Internet using only one public IP address. Attempting to connect to the VPN from behind a NAT will sometimes fail. Most of the time, the NAT can be configured to pass the proper ports and protocols (the IPsec ports are UDP 500 and 1701; the PPTP port is TCP 1723; the GRE protocol is IP 47; the ESP and AH ports are IP 50 and 51, respectively), but not always.

If your computer's IP address falls into one of the following ranges (where x is any number from 0-255), either talk to your ISP about changing to a public IP address, or contact the manufacturer of your router, proxy server, or NAT device about how to configure it to pass VPN connections through:


For instructions on how to determine your current IP address, see Find your computer's IP address

Note: The following may also be helpful when establishing a VPN connection:

  • Make sure you are connecting to the correct server. See the link for your operating system in About the IU VPN.
  • Clear your DNS cache.
  • Release and renew your IP number.

    For help, see Microsoft Support.

This is document akkn in the Knowledge Base.
Last modified on 2018-01-18 12:58:31.

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