Quiz Entry - updated: 2026.07.14
Which Cisco command sets the M-flag versus the O-flag in a router's Advertisements, and what does each tell hosts?
ipv6 nd managed-config-flag sets the M-flag (use Stateful DHCPv6); ipv6 nd other-config-flag sets the O-flag (SLAAC for the address, DHCPv6 for other settings).
The Router Advertisement flags discussed conceptually map to concrete interface commands:
| Command | Flag | Tells hosts to… |
|---|---|---|
ipv6 nd other-config-flag |
O | use SLAAC for the address, fetch DNS/NTP via Stateless DHCPv6 |
ipv6 nd managed-config-flag |
M | get the address itself from Stateful DHCPv6 |
| (neither) | — | pure SLAAC |
On the same router you also define the DHCPv6 pool — a pool with only dns-server/domain-name and no address prefix is stateless; adding address prefix 2001:db8:acad:a::/64 makes it stateful.
Tip: "Managed = the address is managed (handed out) by DHCP"; "Other = only the other info comes from DHCP." That mnemonic decodes both flags instantly.