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Troubleshooting Connection Problems

Connection problems usually fall into three categories as listed below. Depending on the category there are a number of steps you can take to first diagnose the problem and come up with a solution.

  • Unable to connect the VPN connection at all
  • The VPN connection successfully connects but drops out after a few minutes
  • The VPN connection successfully connects but you're unable to use network services through it

The sections below outline how to solve most problems for each of the above categories. If you're still stuck it's recommended that you get in touch with your VPN Provider. If you're unsure who this is please see the How Do I Find Out Who My VPN Provider Is? article.

Unable To Connect The VPN Connection

If Viscosity's icon spins forever, or you receive an error message indicating a connection could not be established, it usually indicates that Viscosity is unable to start the connection or connect to the VPN server.

To resolve this you should first check the OpenVPN log. The OpenVPN log will contain detailed information regarding your connection, and it will usually indicate why you are unable to connect. See the Viewing the OpenVPN Log article for more information.

There are several common error messages you may encounter in the OpenVPN log. Solutions to these can be found in the Common OpenVPN Errors category.

If the OpenVPN log is blank, or doesn't contain any helpful information, you may have to turn to the Console Log on Mac or the Event Viewer on Windows to investigate further. See the Viewing the Console Log article or Viewing the Event Viewer article for further information.

The VPN Connection Drops Out

In some instances you may be able to successfully connect your VPN connection, however it drops out after a few minutes.

The first thing to check is to make sure your computer's network connection isn't dropping out. Depending on the configuration on your VPN connection even a very brief network dropout could cause the VPN connection to dropout as well. If you're connected to Wi-Fi make sure the connection isn't weak, or better yet try connecting via a ethernet cable. Also ensure that a network router or modem isn't briefly disconnecting from the internet.

Another common cause of dropouts is another computer trying to connect using the same authentication credentials at the same time. Some VPN servers may be configured to only allow a single connection from an account/certificate at a time, with new connections causing the connected connection to dropout. Make sure you haven't left the VPN connection running on another computer or device before attempting to connect.

Otherwise dropouts are often related to incorrect settings on either the server or in Viscosity. More information about what caused the dropout will be available in the OpenVPN log. See the Viewing the OpenVPN Log article for how to view this log. Solutions to most dropout-causing errors can be found in the Common OpenVPN Errors category.

Unable To Use The VPN Connection

You should check the OpenVPN log as your first step. The OpenVPN log will contain detailed information regarding your connection, and may contain warning or error messages. See the Viewing the OpenVPN Log article for more information. Check the Common OpenVPN Errors category for solutions to any error messages or warnings you may find.

If no helpful information can be found in the OpenVPN log, you may have to turn to your computer's inbult utilities to determine the cause of the problem. Most connectivity issues are either a DNS problem or a routing problem.

Checking For A DNS Problem

You can check to see whether a DNS problem is present like so:

macOS

  1. Open the Terminal application. This can be found at /Applications/Utilities/Terminal.app
  2. Try pinging a server that you know you should be able to access through the VPN by it's IP address. For example, if you know you should be able to access Google through your VPN connection, try entering "ping 8.8.8.8" (without quotes) as the address to ping, and press Enter.
  3. If you get replies (e.g. "64 bytes from 8.8.8.8") it means you can successfully contact the server. If however you don't get any replies (e.g. "0 packets received"), it's likely you have a routing issue (see below), rather than a DNS problem.
  4. If you successfully get replies, try pinging a server using it's DNS name, for example "www.google.com". If you get a "cannot resolve" error, it means you have a DNS problem.

Windows

  1. Open the Command Prompt application. This can be done by clicking the Start button and typing "Command Prompt" into the search field.
  2. Try pinging a server that you know you should be able to access through the VPN by it's IP address. For example, if you know you should be able to access Google through your VPN connection, try entering "ping 8.8.8.8" (without quotes) as the address to ping, and press Enter.
  3. If you get replies (e.g. "Reply from 8.8.8.8: bytes=32 time=14ms TTL=57") it means you can successfully contact the server. If however you don't get any replies (e.g. "Request timed out."), it's likely you have a routing issue (see below), rather than a DNS problem.
  4. If you successfully get replies, try pinging a server using it's DNS name, for example "ping www.google.com". If you get a "Ping request could not find host" error, it means you have a DNS problem.

You should also try the "Checking Which DNS Servers Are Being Used" section in the Configuring DNS and WINS settings article to make sure Viscosity is correctly setting the DNS server/s on your computer.

Checking For A Routing Problem

You can check to see whether a routing problem is present like so:

macOS

  1. Open the Terminal application. This can be found at /Applications/Utilities/Terminal.app
  2. Type netstat -rn and press Return/Enter on your keyboard.
  3. Once the routing table is displayed, check to make sure that routes exist (the "Destination") for the traffic you want to go through the VPN connection. If the routes are not present, you can add them under the "Networking" tab in Viscosity when editing your VPN connection.
  4. You should also check that the routes are using the correct Gateway (typically an internal address for your VPN server), and the correct network interface (Netif). If the routes have been added to the wrong interface, try adding the command "route-delay auto" (without quotes) to the commands area (under the Advanced tab) in Viscosity when editing your connection.

Windows

  1. Open the Command Prompt application. This can be done by clicking the Start button and typing "Command Prompt" into the search field.
  2. Type in "route print" without quotes and press Enter.
  3. Once the routing table is displayed, check to make sure that routes exist (the "Destination") for the traffic you want to go through the VPN connection. If the routes are not present, you can add them under the "Networking" tab in Viscosity when editing your VPN connection.
  4. You should also check that the routes are using the correct Gateway (typically an internal address for your VPN server), and the correct network interface (Interface). A correct network interface will have the same IP address displayed as the Client IP in the Details Window. If the routes have been added to the wrong interface, try adding the command "route-delay 20" (without quotes) to the commands area (under the Advanced tab) in Viscosity when editing your connection.
  5. If you see two routes with the same Destination but different Gateways, this means you have a routing clash between the remote network and local network. This will need to be resolved, usually by changing one of the networks IP ranges, or you will have routing issues.

If you'd like to continue troubleshooting connection problems yourself, please refer to the Support Forum for a wealth of further information, or the OpenVPN Mailing List.

Slow Connection Speed Over VPN

If you are experiencing much slower connection speed when connected to a VPN server than you would normally have directly through your ISP, there are a few things you can try:

  • If you are using a TCP connection, try a UDP connection instead
  • Try connecting to a different server
  • Try a server that is geographically closer to you.

If none of these options help, the best contact is your VPN Provider, as they will be able to recommend a configuration or server specific to their service. If you are unsure who your VPN Provider is, please see the How Do I Find Out Who My VPN Provider Is? article.