Networks Tit-Bits


  • A Flat Network
    • A network in which all stations can reach other without going through any intermediary hardware devices, such as a bridge or router. A flat network is one network segment.


  • HUB
    • Plug some computers into this, and all traffic is shared. In other words, if computer 1 talks to computer 3, computer 2 will also hear what computer 1 said. Usually computer 2 just discards traffic not meant for it, but it does tend to burden the network.
    • If computer 1 talks to computer 3, computer 2 hears nothing. On high-traffic networks, this means downloads & uploads go a little faster for everyone. On low-traffic networks (home networks) users typically don't notice a difference.
    • Plug some computers into this, and it'll use port forwarding, IP masquerading, and NAT to allow computers to share an IP address and connect to the internet. Cheap routers use HUB technology, good routers use SWITCH technology.
    • It is sometimes useful to divide one physical network (such as an Ethernet segment) into two separate network segments without having to create IP subnets and use a router to connect the segments together. A device that connects two networks together in this fashion is called a bridge. The bridge works by learning the MAC layer addresses (Ethernet addresses) of the devices on each of its network interfaces. It forwards traffic between two networks only when its source and destination are on different networks.



  • netstat -s -P ip : Show network stack statistics for the ip protocol.
  • netstat -i : Show network interface statistics.
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