IPv6Privileged EXEC

show ipv6 interface [interface]

Shows full IPv6 interface configuration including addresses, NDP settings, and RA advertisement flags.

Syntax·Privileged EXEC

show ipv6 interface [<interface-type><interface-number>]

When to Use This Command

Verifying IPv6 addresses and link-local address on an interface.
Checking RA M and O flag settings for DHCPv6 configuration verification.
Troubleshooting NDP settings (reachable time, retransmit interval).
Confirming IPv6 forwarding is enabled on an interface.

Command Examples

Detailed IPv6 interface output

R1# show ipv6 interface GigabitEthernet0/1

GigabitEthernet0/1 is up, line protocol is up
  IPv6 is enabled, link-local address is FE80::1
  No Virtual link-local address(es):
  Global unicast address(es):
    2001:db8:1::1, subnet is 2001:db8:1::/64
  Joined group address(es):
    FF02::1
    FF02::2
    FF02::1:FF00:1
  MTU is 1500 bytes
  ICMP error messages limited to one every 100 milliseconds
  ICMP redirects are enabled
  ND DAD is enabled, number of DAD attempts: 1
  ND reachable time is 30000 milliseconds (using 30000)
  ND advertised reachable time is 0 (unspecified)
  ND router advertisements are sent every 200 seconds
  ND router advertisements live for 1800 seconds
  ND advertised default router preference is Medium
  Hosts use stateful autoconfig for addresses.
  Hosts use DHCP to obtain other configuration.

Link-local FE80::1 is auto-configured. Global unicast 2001:db8:1::1/64 is manually assigned. 'Stateful autoconfig for addresses' = M flag set. 'DHCP to obtain other configuration' = O flag set. FF02::1 (all-nodes) and FF02::2 (all-routers) multicast groups are joined automatically.

Brief overview of all IPv6 interfaces

R1# show ipv6 interface brief

GigabitEthernet0/0     [up/up]
    FE80::1
    2001:DB8:FFFF::1
GigabitEthernet0/1     [up/up]
    FE80::1
    2001:DB8:1::1
Loopback0              [up/up]
    FE80::1
    2001:DB8::1

Brief view shows all IPv6-enabled interfaces, their state, and addresses. Useful for a quick overview without the NDP detail.

Understanding the Output

Key elements: link-local address (FE80::x/10, always present when IPv6 is enabled), global unicast address(es), joined multicast groups (FF02::1 all-nodes, FF02::2 all-routers, FF02::1:FFxx:xxxx solicited-node), RA interval and lifetime, M/O flag interpretation, and DAD (Duplicate Address Detection) status. Use 'brief' keyword for a quick summary of all interfaces.

CCNA Exam Tips

CCNA exam tip: Every IPv6-enabled interface has a link-local address (FE80::/10) even if no global address is configured.

CCNA exam tip: 'show ipv6 interface brief' is the IPv6 equivalent of 'show ip interface brief' for a quick status check.

CCNA exam tip: The M and O flag status ('stateful autoconfig' or 'stateless autoconfig') is visible in this output — key for DHCPv6 troubleshooting.

CCNA exam tip: Multicast group FF02::2 (all-routers) is only joined if 'ipv6 unicast-routing' is enabled.

Common Mistakes

Mistake 1: Forgetting that every IPv6-enabled interface has a link-local (FE80::) address — not just interfaces with global addresses.

Mistake 2: Ignoring the M/O flag output when troubleshooting DHCPv6 — this output shows exactly what flags clients see in RAs.

Mistake 3: Confusing 'show ipv6 interface' (detailed per-interface) with 'show ipv6 interface brief' (summary of all).

Related Commands

ipv6 address [prefix/len]

Assigns a global unicast or link-local IPv6 address to an interface, enabling IPv6 routing on that interface.

ipv6 enable

Enables IPv6 processing on an interface, allowing the interface to forward IPv6 traffic and participate in IPv6 routing protocols.

ipv6 nd managed-config-flag

Sets the Managed (M) flag in IPv6 Router Advertisement (RA) messages sent from this interface. When M=1, clients are instructed to obtain their IPv6 address from a DHCPv6 server (stateful DHCPv6) rather than using SLAAC.

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