debugging internet

- 2 minutes read - 327 words

My standard plan for debugging internet connections:

  1. Can we reach stuff from some other device?

    Usually, connection problems are something like “My iPad isn’t working,” which is caused by a flash of light in the sky, like when Swamp gas from a weather balloon gets trapped in a thermal pocket and reflects the light from Venus."

    So try something other than your iPad on your WiFi to isolate whether it is a WiFi network problem or a “iPad"problem.

    If it is a wifi problem:

  2. Can we reach the router?
    Basically, this means running:
    ping 192.168.1.1 except that sometimes it is some other IP address. In those cases, run something like:
    windows> ipconfig /all
    linux$ route -nv
    osx$ route -n get default | grep gateway

    If this doesn’t work, it means something is screwed up with the modem and/or router.

    If it does, it means something else is wrong, so continue:

  3. Can we reach the external modem IP address?

  4. Can we reach another external IP address?
    Usually, this means running
    ping 8.8.8.8 which should be a very reliable IP address.
    If this doesn’t work–i.e. anything other than output like:
    PING 8.8.8.8 (8.8.8.8): 56 data bytes
    64 bytes from 8.8.8.8: icmp_seq=0 ttl=46 time=88.441 ms
    ^C
    — 8.8.8.8 ping statistics —
    1 packets transmitted, 1 packets received, 0.0% packet loss
    round-trip min/avg/max/stddev = 88.441/88.441/88.441/0.000 ms (on OSX) indicates that your connection between the modem and the internet is degraded.

    If that’s not it, continue:

  5. Can we reach another website by its URL?

    Try visiting =http://puppies.com/= in your web browser and see if that works.

    If not, it probably means that DNS is degraded (i.e., the system that transforms puppies.com into the IP address 184.168.221.26 is broken somehow.

    Usually, this means that your internet provider has DNS server downtime. A couple of options here are to set your primary and secondary DNS to Google’s:

    8.8.8.8
8.8.4.4

    or, in a pinch, OpenDNS':

    208.67.222.222
208.67.220.220

    You might want to switch them back later.