control/diagnose IPv6 Neighbor
Discovery Protocol (NDP)
ndp command manipulates the address
mapping table used by the Neighbor Discovery Protocol (NDP).
-a(dump NDP entries) every wait seconds.
- Dump the currently existing NDP entries. The following information will be
- The IPv6 address of the neighbor.
- Linklayer Address
- The linklayer address of the neighbor. If the address is not available, it will be displayed as “(incomplete)”.
- The network interface associated with the neighbor cache entry.
- The time until expiry of the entry. If the entry is marked “permanent”, it will never expire.
- The state of the neighbor cache entry, as a single letter:
- Unknown state (should never happen).
- Flags on the neighbor cache entry, in a single letter. They are: local (‘l’), Router (‘R’) and proxy neighbor advertisement (‘p’). This field may be followed by a decimal number, representing the number of NS probes the node has sent during the current state.
- Erase all the NDP entries.
- Delete the specified NDP entry.
- Parse entries from file to be inserted in the
neighbor cache. See the
-soption for a description of the file format.
- Harmonize consistency between the routing table and the default router list; install the top entry of the list into the kernel routing table.
-iinterface [flag ...]
- View ND information for the specified interface. If additional arguments
ndpsets or clears the specified flags for the interface. Each flag should be separated by whitespace or tab characters. Possible flags are as follows. All of the flags can begin with the special character ‘
-’, which means the flag should be cleared. Note that
--would be needed before
-fooin this case.
- Turn on or off NUD (Neighbor Unreachability Detection) on the interface. NUD is usually turned on by default.
- Specify whether or not to accept Router Advertisement messages received on the interface. Note that the kernel does not accept Router Advertisement messages unless the interface is configured for inet6 autoconfiguration.
- Do not try to resolve numeric addresses to hostnames.
- Flush all the entries in the prefix list.
- Show the prefix list.
- Flush all the entries in the default router list.
- Show the default router list.
-snodename ether_addr [
- Register an NDP entry for the node called nodename with the Ether address
ether_addr. The Ethernet address is given as six hexadecimal bytes
separated by colons. The entry will be permanent unless the word
tempis given in the command. If the word
proxyis given, this system will act as an ND Proxy server, responding to requests for nodename even though the node address is not its own.
- Print a timestamp on each entry, making it possible to merge output with
tcpdump(8). Most useful when used with
- Set the routing domain to be used. The default is 0.
ndp utility exits 0 on success,
and >0 if an error occurs.
ip6(4), sysctl.conf(5), arp(8), sysctl(8), tcpdump(8)
ndp command first appeared in the WIDE
Hydrangea IPv6 protocol stack kit.