networktest

This tool answers the question: am I connected to a (local) network and do I have internet connectivity?

How does it work?

While the question "can this computer reach the Internet?" is quite easily answered by trying to load http://www.google.com in a browser, common network configurations have a number of parameters that may vary between one case of "it's not working" and the next.

networktest aims to be a tool that makes it easy to establish the key network configuration characteristics and get a quick idea of what might be wrong. It is a smoke test of your network setup.

The questions we ask are:

1. Am I connected to any networks? If so, what kind of network are they? Loopback interface? Link-local? Or is it a network that allows me to route packets to the Internet (the kind we want)?
2. What ip addresses do I have on the networks I'm connected to? These are addresses that should be reachable (ie. pingable) from myself.
3. What gateways do I have? A gateway (or router) is a host on my network that allows me to route packets to other networks.
4. Can I reach Internet hosts by ip? If so, my gateway is working.
5. What DNS servers (nameservers) do I have? DNS servers allow me to resolve Internet hostnames to ip addresses.
6. Can I reach Internet hosts by hostname? If so, I have "Internet connectivity" in the common sense.

Downloading binaries

The easiest way to use networktest is to download a binary release.

You will need to know whether you need the 32bit or the 64bit version, depending on your operating system. Most operating systems these days are 64bit.

networktest is written in Go and targets Linux, FreeBSD, OS X (Darwin), and Windows.

Building from source

Tools required to build from source:

• go >= 1.5
• git >= 1.8.1.6
• python >= 2.6
• make (optional)

If you have make installed just use that:

$ make

If you don't (eg. Windows):

$ python build.py --build

You can find the binary in bin/havenet.

Usage

To detect IPv4 networking (working internet connection):

$ havenet
Platform: Linux
 + Scanning for networks...
    <lo>              127.0.0.0 / 255.0.0.0
    <docker0>        172.17.0.0 / 255.255.0.0
    <eth0>          192.168.1.0 / 255.255.255.0
    <wlan0>         192.168.1.0 / 255.255.255.0
 + Detecting ips...
    <lo>              127.0.0.1 / 255.0.0.0        ping: 0.059 ms
    <docker0>        172.17.0.1 / 255.255.0.0      ping: 0.066 ms
    <eth0>          192.168.1.6 / 255.255.255.0    ping: 0.065 ms
    <wlan0>        192.168.1.10 / 255.255.255.0    ping: 0.052 ms
 + Detecting gateways...
    <eth0>          192.168.1.1  ping: 0.746 ms
     ip:            192.168.1.6
     ip:           192.168.1.10
 + Testing internet connection...
    b.root-servers.net.   192.228.79.201  ping: 177.8 ms
 + Detecting dns servers...
            8.8.8.8  ping: 41.79 ms
 + Testing internet dns...
         debian.org  ping: 111.9 ms
       facebook.com  ping: 133.5 ms
          gmail.com  ping: 39.29 ms
         google.com  ping: 83.51 ms
          yahoo.com  ping: 174.4 ms

To detect IPv6 networking (no internet connection):

$ havenet -6
 + Scanning for networks...
    <lo>                                            ::1 / 128  [scope: host]
    <eth0>                                       fe80:: /  64  [scope: link]
    <wlan0>                                      fe80:: /  64  [scope: link]
 + Detecting ips...
    <lo>                                            ::1 / 128  ping: 0.047 ms
    <eth0>                    fe80::16da:fae1:c9ea:a4b9 /  64  ping: N/A
    <wlan0>                   fe80::762f:fe64:b7c7:7b7a /  64  ping: N/A
 + Detecting gateways...
    none found