If you’re having trouble connecting to your company’s network through the Cisco VPN client, check the error code. If you see “Secure VPN connection terminated locally by the client. Reason 412″ it means that the software VPN client detected that the VPN server isn’t responding and has deleted the connection.

Cisco VPN error 412 – What Causes it?

The following are the main causes of a VPN 412 error:

• You’re behind a firewall that’s blocking ports UDP 4500/500 and/or ESP.
• The VPN client is using connecting on TCP and the default TCP port 10000 for NAT-T is blocked.
• Your internet connection isn’t stable and some packets aren’t reaching the concentrator/server or the replies from the server/concentrator aren’t getting to the client.
• The VPN client is behind a NAT device and the VPN server doesn’t have NAT-T enabled. If this is the case, you won’t be able to send or receive traffic. It will connect, but then nothing.  After some time the software client deletes the VPN tunnel.

VPN error 412 Possible solutions

To fix the problem, try the following:

• If you are using wireless, try to connect with cable. 
• Turn your firewall off, then test the connection to see whether the problem still occurs. If it doesn’t then you can turn your firewall back on, add exception rules for port 500, port 4500 and the ESP protocol in your firewall.
• Turn on NAT-T/TCP in your profile, and unblock port 10000 in your firewall.
• Edit your profile with your editor and change ForceKeepAlive=0 to 1
• Configure your firewall to permit UDP ports 500 and 62515. These are required for Cisco VPN client.
• Verify that your client is actually transmitting packets: Start a command window and run the command “netstat -s -p ip 60″ to see IP send and receive packet counts.

Does this solve your Cisco VPN error 412 problem? Let us know in the comments.