This will be alphabetically sorted bunch of simple but hard to find facts about some very important networking features and protocols. It is a page about interesting not well-known facts that for me were a surprise first time when I hear them.

It will at some point go active with some advanced search option but until is only a page long it will be like this:


Welcome to Tips & Tricks on HowDoesInternetWork


  • IPv6
    • Pinging IPv4 is returning IPv6?
      • If you are connected with your computer (Win computer) to some LAN network across DirectAccess technology it will probably be the reason that tunneling technology is returning you the IPv6 address.
  • OSPF
    • Open Shortest Path First
      • When configuring OSPF process on a router the PID (Process ID) does not need to be the same as on other routers to make it possible to form neighbors. One router can be #router ospf 1 and other router can be #router ospf 2 but they will form a relation if they have hello and death timers set to equal values.
  • Network Monitoring
    • What’s the best tool to monitor your network and that is not expensive (free)?
      • Security Onion is a great group of people developing open source network monitoring tool that has probably more capabilities that all other commercial tools together. You can find the details here:
  • Static routes
    • IPv4 It is very interesting that for static route configured using exit interface (#ip route fa0/0) Administrative distance is 1 and for the static route configured using next-hop IP address (3ip route Administrative distance is 0.
    • IPV6 is different, here both static routes with exit interface or next-hop address have the Administrative distance of 1.