# Neighbor Discovery

## nv show interface <interface-id> ipv6 neighbor-discovery

Shows ND settings for an interface.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery
                          applied
    --------------------  -------
    enable                on
    router-advertisement
      enable              off
    home-agent
      enable              off

## nv show interface <interface-id> ipv6 neighbor-discovery dnssl

Shows the DNSSLdomain suffixes configured on the specified interface.

You must use `--applied` with this command to show the output.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery dnssl`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery dnssl --applied
    No Data

## nv show interface <interface-id> ipv6 neighbor-discovery dnssl <domain-name-id>

Shows configuration information for the specified DNSSLdomain suffix.

You must use `--applied` with this command to show the output.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery dnssl <domain-name-id>`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.
`<domain-name-id>` | The domain portion of a hostname (RFC 1123) or an internationalized hostname (RFC 5890).

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery dnssl accounting.nvidia.com --applied
    --------  --------
    lifetime  infinite

## nv show interface <interface-id> ipv6 neighbor-discovery home-agent

Shows Home Agent configuration for an interface, such as the maximum amount of time the router acts as a Home Agent and the router preference.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery home-agent`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery home-agent
                applied
    ----------  -------
    enable      on
    lifetime    200
    preference  0

## nv show interface <interface-id> ipv6 neighbor-discovery prefix

Shows the ND prefixes for the specified interface.

You must use `--applied` with this command to show the output.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery prefix`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery prefix --applied
    No Data

## nv show interface <interface-id> ipv6 neighbor-discovery prefix <prefix-id>

Shows ND prefix configuration for the specified interface, such as the amount of time the prefix is valid for on-link determination, the amount of time that addresses generated from a prefix remain preferred, and if the specified prefix uses the IPv6 autoconfiguration setting.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery prefix <ipv6-prefix-id>`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.
`<ipv6-prefix-id>` | The IPv6 address and route prefix.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery prefix 2001:db8:1::100/32
                        applied
    ------------------  ----------
    autoconfig          on
    off-link            on
    preferred-lifetime  100000
    router-address      on
    valid-lifetime      2000000000

## nv show interface <interface-id> ipv6 neighbor-discovery rdnss

Shows the RDNSS configured on the specified interface.

You must use `--applied` with this command to show the output.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery rdnss`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery rdnss --applied
    No Data

## nv show interface <interface-id> ipv6 neighbor-discovery rdnss <address-id>

Shows configuration for the specified RDNSS configured on the specified interface.

You must use `--applied` with this command to show the output.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery rdnss <ipv6-address-id>`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.
`<ipv6-address-id>` | The IPv6 address of the RDNSS.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery rdnss 2001:db8:1::100 --applied
    No Data

## nv show interface <interface-id> ipv6 neighbor-discovery router-advertisement

Shows router advertisement configuration for an interface, such as the hop limit value advertised in a router advertisement message, the maximum amount of time that router advertisement messages can exist on the route, the interval at which neighbor solicitation messages retransmit, and if fast transmit mode is on.

In Cumulus Linux 5.14 and earlier, the command is `nv show interface <interface-id> ip neighbor-discovery router-advertisement`.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface name.

### Version History

Introduced in Cumulus Linux 5.1.0

### Example

    cumulus@switch:~$ nv show interface swp1 ipv6 neighbor-discovery router-advertisement
                       applied
    -----------------  -------
    enable             off
    fast-retransmit    off
    hop-limit          64
    interval           600000
    interval-option    off
    lifetime           1800
    managed-config     off
    other-config       off
    reachable-time     0
    retransmit-time    0
    router-preference  medium

## nv show interface neighbor

Shows all the entries in the IP neighbor table.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface neighbor
    Interface      IP/IPV6                    LLADR(MAC)         State      Flag
    -------------  -------------------------  -----------------  ---------  ----------
    eth0           192.168.200.251            48:b0:2d:00:00:01  stale
                   192.168.200.1              48:b0:2d:aa:8b:45  reachable
                   fe80::4ab0:2dff:fe00:1     48:b0:2d:00:00:01  reachable  router
    peerlink.4094  169.254.0.1                48:b0:2d:3f:69:d6  permanent
                   fe80::4ab0:2dff:fe3f:69d6  48:b0:2d:3f:69:d6  reachable  router
    swp51          169.254.0.1                48:b0:2d:a2:4c:79  permanent
                   fe80::4ab0:2dff:fea2:4c79  48:b0:2d:a2:4c:79  reachable  router
    swp52          169.254.0.1                48:b0:2d:48:f1:ae  permanent
                   fe80::4ab0:2dff:fe48:f1ae  48:b0:2d:48:f1:ae  reachable  router
    swp53          169.254.0.1                48:b0:2d:2d:de:93  permanent
                   fe80::4ab0:2dff:fe2d:de93  48:b0:2d:2d:de:93  reachable  router
    swp54          169.254.0.1                48:b0:2d:80:8c:21  permanent
                   fe80::4ab0:2dff:fe80:8c21  48:b0:2d:80:8c:21  reachable  router
    vlan10         10.1.10.3                  44:38:39:22:01:78  permanent
                   10.1.10.101                48:b0:2d:a1:3f:4b  reachable
                   10.1.10.104                48:b0:2d:1d:d7:e8  noarp      |ext_learn
                   fe80::4ab0:2dff:fea1:3f4b  48:b0:2d:a1:3f:4b  reachable
                   fe80::4ab0:2dff:fe1d:d7e8  48:b0:2d:1d:d7:e8  noarp      |ext_learn
                   fe80::4638:39ff:fe22:178   44:38:39:22:01:78  permanent
    ...

## nv show interface <interface-id> neighbor

Shows all the entries in the IP neighbor table for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor
    ipv4
    =========
        IPV4         LLADR(MAC)
        -----------  -----------------
        10.5.5.51    00:00:5e:00:53:51
        169.254.0.1  48:b0:2d:a2:4c:79
    ipv6
    =========
        IPV6                       LLADR(MAC)
        -------------------------  -----------------
        fe80::4ab0:2dff:fea2:4c79  48:b0:2d:a2:4c:79

## nv show interface <interface-id> neighbor ipv4

Shows all IPv4 table entries for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp1 neighbor ipv4
    IPV4         LLADR(MAC)
    -----------  -----------------
    169.254.0.1  48:b0:2d:4d:1a:ed

## nv show interface <interface-id> neighbor ipv4 <neighbor-id>

Shows table entries for an interface with a specific IPv4 address.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv4 address of the neighbor.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv4 169.254.0.1
    lladdr
    =========
        LLADR(MAC)         State      Flag
        -----------------  ---------  ----
        48:b0:2d:4d:1a:ed  permanent

## nv show interface <interface-id> neighbor ipv4 <neighbor-id> lladdr <lladdr-id> state

Shows the state of the neighbor in the IPv4 neighbor table for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv4 address of the neighbor.
`<lladdr-id>` | The MAC address associated with IPv4 address.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv4 169.254.0.1 lladdr 48:b0:2d:4d:1a:ed state
    operational  applied
    -----------  -------
    permanent

## nv show interface <interface-id> neighbor ipv4 <neighbor-id> lladdr <lladdr-id> flag

Shows the flag set for the neighbor in the IPv4 neighbor table for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv4 address of the neighbor.
`<lladdr-id>` | The MAC address associated with IPv4 address.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv4 169.254.0.1 lladdr 48:b0:2d:4d:1a:ed flag
      operational  applied
       -----------  ---------
       is-router    is-router

## nv show interface <interface-id> neighbor ipv6

Shows all IPv6 table entries for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp1 neighbor ipv6
    IPV6                       LLADR(MAC)
    -------------------------  -----------------
    fe80::1e34:daff:fe6c:dd8   1c:34:da:6c:0d:d8
    fe80::3e2c:30ff:fe4b:800   3c:2c:30:4b:08:00

## nv show interface <interface-id> neighbor ipv6 <neighbor-id>

Shows table entries for an interface with a specific IPv6 address.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv6 address of the neighbor.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv6 fe80::4ab0:2dff:fea2:4c79
    lladdr
    =========
        LLADR(MAC)         State      Flag
        -----------------  ---------  ----
        00:00:5E:00:53:51  permanent

## nv show interface <interface-id> neighbor ipv6 <neighbor-id> lladdr <lladdr-id> state

Shows the state of the neighbor in the IP neighbor table for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv6 address of the neighbor.
`<lladdr-id>` | The MAC address associated with IPv6 address.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv6 fe80::4ab0:2dff:fea2:4c79 lladdr 00:00:5E:00:53:51 state
    No Data

## nv show interface <interface-id> neighbor ipv6 <neighbor-id> lladdr <lladdr-id> flag

Shows the flag set for the neighbor in the IP neighbor table for the specified interface.

### Command Syntax

Syntax | Description
--- | ---
`<interface-id>` | The interface.
`<neighbor-id>` | The IPv6 address of the neighbor.
`<lladdr-id>` | The MAC address associated with IPv6 address.

### Version History

Introduced in Cumulus Linux 5.7.0

### Example

    cumulus@switch:~$ nv show interface swp51 neighbor ipv6 fe80::4ab0:2dff:fea2:4c79 lladdr 00:00:5E:00:53:51 flag
      operational  applied
       -----------  ---------
       is-router    is-router

## nv show system global nd

Shows ND settings, such as the neighbor base reachable timer and garbage collection settings.

### Version History

Introduced in Cumulus Linux 5.6.0

### Example

    cumulus@switch:~$ nv show system global nd
                                  operational  applied
    ----------------------------  -----------  -------
    base-reachable-time           50           50
    garbage-collection-threshold
      effective                   17920
      maximum                     20480
      minimum                     128

## nv show system global nd garbage-collection-threshold

Shows the ND garbage collection threshold settings.

### Version History

Introduced in Cumulus Linux 5.6.0

### Example

    cumulus@switch:~$ nv show system global nd garbage-collection-threshold
               operational  applied
    ---------  -----------  -------
    effective  35840
    maximum    40960
    minimum    128