## Manipulate ARP and neighbor discovery caches ##

[Author](authors.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

[Reviewer](technical_reviewers.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

[Reviewer](technical_reviewers.html): _name_ _[[contact]]_ _[[BSD_flavour]]_

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### Concept ###

Understand basic ARP(((ARP))) theory as well
as the neighbor discovery cache(((neighbor discovery cache))) used
on IPv6(((IPv6))) networks. Be able to view,
modify and clear these caches and recognize when it is necessary to
do so.


### Introduction ###

arp: address resolution display and control

ndp: control/diagnose IPv6 neighbor discovery protocol

how arp works:

machine1 asks broadcast "who has x.x.x.x?"

broadcast request gets forwarded to all listeners

machine2 answers broadcast request with "machine2 has x.x.x.x"

view arp cache:

""arp -a
""ndp -a 

modify arp cache:

""arp -s hostname ether\_addr (adds arp entry)
""arp -d hostname (deletes arp entry)
""ndp -s nodename ether\_addr [temp] [proxy]
""ndp -d hostname

clear arp cache:

""arp -d -a (combining -d[elete] with -a[ll] deletes all entries)
""ndp -c (erases all ndp entries)


### Examples ###


### Practice Exercises ###


### More information ###

arp(8), ndp(8)


