Episode 231

Networking Part 2 with Steve Ovens


May 11th, 2021

56 mins 11 secs

Your Host
Special Guest

About this Episode

In this episode Steve joins us again to discuss networking. Building on the knowledge from our last episode we dig further into ipv6 and other network technology!

-- During The Show --

01:00 - VLAN question - Scott
  • Management VLan is for admin not printers etc
  • Set the switch to only allow access on the management VLan
  • Use firewall rules to allow or deny cross VLan access
08:10 - Replace Unify with TP Link Omada? - Charlie
  • Checking it out, will get back to you
09:00 - Just FYI problem accessing Wireguard tutorial - Paul
09:30 - What Router Should I buy? - Nik
12:15 IPv4
  • Broadcast traffic - sends a packet to everyone, not forwarded by routers
  • Broadcast Domain - Any computer that can hear a broadcast packet
  • ARP Table - Table that matches switch port to mac address
  • Computers also keep ARP Tables - Including Host Name, MAC Address, IP Address
  • Rebooting a switch will cause it to rebuild the ARP Table
  • Private IP Addresses - IPv4 Addresses set aside for internal networks
  • RFC 1918
  • NAT - Network Address Translation - Public IP <-> Private IP
  • [IP Chicken](ipchicken.com)
  • Router typically hands out DNS Server+IP Address+Hostname
30:00 IPv6
  • IPv6 packet types
    • Anycast
    • Multicast
    • Link-Local
  • IPv6 Anycast - Send out a packet to an IP address, expecting multiple devices to have the same IP Address but only the closest responds
  • IPv6 Multicast - Tries to only hit intended IP addresses
  • Link-Local - Automatically assigned, non route-able, Required for IPv6
  • Unique-Local - Private or Public route-able IP address
  • Host bit of IPv6 identifies your device across networks
41:50 Reading IPv6
  • First hextet = IANA Assigned prefix
  • Second hextet = Your Geographical region
  • Third hextet = Your ISP
  • Fourth hextet = Your Network

  • Leading zeros can be omitted

    This IP:


    Can be expressed like this:


  • IPv6 Loopback address

48:00 Getting an address
  1. Computer sends an icmpv6 packet called a Router Solicitation
  2. The router responds with its information (with its Link Local address)
  3. Either the router generates an ipv6 based on the requesting computers MAC address OR the computer chooses its own IP address
  4. The computer sends a Neighbor Solicitation packet which is basically the computer attempting to ping a device on the network with its IP address to see if its chosen IP already exists
  • IPv6 you are on the internet by default unlike IPv4 in most setups

  • "Host" bits are based on your MAC address, which can be used for finger printing/tracking


Address broken into hextets

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