Go Code Quality: http://goreportcard.com/report/IPSecDiagTool/IPSecDiagTool

IPSecDiagTool is a diagnosis tool for the continuous monitoring of IPSec VPN tunnels. It has two main features. Firstly it's capable of passively detecting packet loss occurring within the IPSec tunnels. If the packet loss exceeds a specified threshold a Syslog warning is automatically dispatched. Secondly IPSecDiagTool can actively determine the exact MTU within a tunnel. This is useful when you're dealing with badly configured routers that block regular ICMP messages outside of the tunnel. IPSecDiagTool is designed to run as a daemon/service, but for testing purposes it also has a interactive mode.

• Passive detection of IPSec packet loss by capturing arriving ESP packets and gathering their sequence numbers.
• Active diagnosis of IPSec fragmentation problems and discovery of the ideal MTU (Maximum Transmission Unit).
• Daemon/service that can bee kept running indefinitely.
• Machine and human readable JSON configuration.
• Optimized for minimal performance impact.

YOUR_GO_WORKSPACE
    bin/
        executables                          # command executable
    pkg/
        packages                             # package object
    src/
        github.com/ipsecdiagtool/ipsecdiagtool/
            .git/                            # Git repository metadata
            .gitignore
            main.go                          # main source file
            build.sh
            update.sh
            README.md
            capture/
                capture.go                   # Captures pcap data
            config/
                config.go                    # Read/write the JSON config file
            logging/
                logging.go                   # Send messages to a Syslog server
            mtu/
                analyze.go                   # Find the MTU for all configured tunnels
            packetloss/
                detect.go                    # Detect packet loss and report to a Syslog server

IPSecDiagTool is being programmed in Golang. You can pull our code into your own application by running go get github.com/ipsecdiagtool/ipsecdiagtool/. Our code is also documented on Godoc.

The MIT License (MIT)

Copyright (c) 2015 Theo Winter, Jan Balmer

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.