ndp

Package ndp implements the Neighbor Discovery Protocol, as described in RFC 4861. MIT Licensed.

The command ndp is a utility for working with the Neighbor Discovery Protocol.

Install the package and utility using go get:

$ go get github.com/mdlayher/ndp/...

To learn more about NDP, and how to use this package, check out my blog: Network Protocol Breakdown: NDP and Go.

Examples

Listen for incoming NDP messages on interface eth0 to one of the interface's global unicast addresses.

$ sudo ndp -i eth0 -a global listen
$ sudo ndp -i eth0 -a 2001:db8::1 listen

Send router solicitations on interface eth0 from the interface's link-local address until a router advertisement is received.

$ sudo ndp -i eth0 -a linklocal rs

Send neighbor solicitations on interface eth0 to a neighbor's link-local address until a neighbor advertisement is received.

$ sudo ndp -i eth0 -a linklocal -t fe80::1 ns

An example of the tool sending a router solicitation and receiving a router advertisement on the WAN interface of a Ubiquiti router:

$ sudo ndp -i eth1 -a linklocal rs
ndp> interface: eth1, link-layer address: 04:18:d6:a1:ce:b8, IPv6 address: fe80::618:d6ff:fea1:ceb8
ndp rs> router solicitation:
    - source link-layer address: 04:18:d6:a1:ce:b8

ndp rs> router advertisement from: fe80::201:5cff:fe69:f246:
    - hop limit:        0
    - flags:            [MO]
    - preference:       0
    - router lifetime:  2h30m0s
    - reachable time:   1h0m0s
    - retransmit timer: 0s
    - options:
        - prefix information: 2600:6c4a:7002💯:/64, flags: [], valid: 720h0m0s, preferred: 168h0m0s