Schlagwort-Archive: ipv6

Reserved for documentation use

Sometimes you have document a network behavior and need example prefixes or AS numbers. Here is a list of some documents and reserved values, which could be useful for this:

  • MAC unicast address (see RFC7042): 00:00:5E:00:53:00 to 00:00:5E:00:53:FF
  • MAC multicast address (see RFC7042): 01:00:5E:90:10:00 to 01:00:5E:90:10:FF
  • IPv4 unicast prefix (see RFC5737)-, and
  • IPv4 multicast prefix (see RFC6676)-
  • IPv6 unicast prefix (see RFC3849)- 2001:DB8::/32
  • IPv6 multicast prefix (see RFC6676)- FF0<any hex value>::DB8:0:0/96
  • AS numbers 16-bit (see RFC5398) – 64496 – 64511
  • AS numbers 32-bit (see RFC5398) – 65536 – 65551
  • Top-Level Domain (see BCP32) – .example


  • Alice and Bob, alternatives for ‚Person A’/’Person B‘ when describing processes in telecommunications; in cryptography Eve (the eavesdropper) is also added.(see Wikipedia)

Differences between VRRPv2 and VRRPv3

During IPv6 testing I discovered several differences between VRRPv2 (RFC 3768 – and VRRPv3 (RFC 5798 – which you should be familiar if you wanna use VRRPv3 for IPv4 and IPv6:

  • VRRPv3is a unified protocol for IPv4 and IPv6
  • Its a real version cut
    • every router in your LAN must speak the same version
    • only hard migration is possible
    • With JunOS 12.2 you can switch via „set protocols vrrp version 3“
  • Authentication dropped in VRRPv3, should be done by sub-protocols
    • the only security you get is by TTL 255 check
  • Virtual MAC Address for IPv4 00-00-5e-00-01-{VID}
  • Virtual MAC Address for IPv6 00-00-5e-00-02-{VID}
  • Sub-Second Advertisments
    •  intervals specified in centiseconds
    • 100 centisecond = 1 second
  • IPv6 need 2 addresses: virtual-link-local addresses + global address
    • since JunOS 12.2 auto-generated link-local/virtual-link-local possible
  • You must have Router-Advertisements enabled
    • thats the new cool way for default-gateway propagation to hosts
IPv4/VRRPv2 vs. IPv6/VRRPv3
IPv4/VRRPv2 vs. IPv6/VRRPv3

You need JunOS 12.2 for the full VRRPv3 implementation of RFC 5798. Prior JunOS versions only implement draft (, which differs in checksum calculation and serveral minor features.