Troubleshooting Client VPN
Use this article to troubleshoot, identify and resolve common client VPN connectivity issues.
Common Causes
- Blocked ports: Verify UDP traffic on ports 500 and 4500 is not reaching the MX security appliance. Check the firewall rules or access control lists on all firewalls between the client and MX security appliance. Try connecting from a client device using a different ISP.
- Client misconfiguration: Verify the client is configured correctly. See Client VPN OS Configuration for more information.
- User account issue: Verify the account is authorized to connect to VPN. Reset the password or connect with a working set of credentials to further isolate the issue.
- Device-specific issue: Try connecting with a different device to verify if it is a device-specific issue. Reset network settings or reset the device if available.
Connection Issues
Unable to Connect to Client VPN from All Devices
Unable to Connect to Client VPN from Some Devices
Basic Troubleshooting Guides
Troubleshooting Client VPN with Packet Captures
Additional Troubleshooting
Slow Connections
If the connection over VPN appears slow, first identify if the connection is slow for everything over the tunnel or only for specific resources. If the connection is slow to an application but normal for other resources via the tunnel, the issue is not likely related to the VPN connection.
VPN speeds depend on a lot of factors including bandwidth on the MX security appliance and client side, number of clients connected to MX or number of VPN tunnels on the MX.