CCNA 200-301 v1.1 quick lookup
IPv6 address space
Unicast scopes, special addresses and the multicast groups that appear in verification output.
Protocol numbers and portsIPv4 masks and block sizesIPv6 address spaceRouting codes and administrative distancesSyslog levels and thresholdsProtocol defaults and timers
From IPv6 address types — the same block lives in that article
IPv6 unicast scopes and special addresses
| Type | Prefix | Behavior |
|---|---|---|
| Global unicast | 2000::/3 (currently 2000::–3fff::) | Routable on the internet, like public IPv4 |
| Unique local (ULA) | fc00::/7 (fd00::/8 in practice) | Private local scope — like RFC 1918 space; not a deprecated scope and not routed on the internet |
| Link-local | fe80::/10 | Mandatory on every IPv6 interface; valid only on the local link, never routed |
| Loopback | ::1 | Host only |
| Unspecified | :: | Source before the host has an address (e.g., during DAD) |
Link-local appears in every show ipv6 interface and is used for next hops, RA and ND — learn to read it.
From IPv6 address types — the same block lives in that article
Common IPv6 multicast groups (ff00::/8)
| Address | Reaches | Seen in |
|---|---|---|
| ff02::1 | All nodes on the link | Neighbor discovery |
| ff02::2 | All routers on the link | Router solicitations |
| ff02::5 | All OSPF routers | OSPFv3 |
| ff02::6 | OSPF DRs | OSPFv3 DR traffic |
| ff02::a | All EIGRPv6 routers | EIGRP for IPv6 |
| ff02::1:ffXX:XXXX | Solicited-node (per unicast address) | NS/DAD — maps the low 24 bits of the target |