Nortel IP Phone 2004 Page 125 of 430IP Phones Description, Installation, and OperationGratuitous Address Resolution Protocol ProtectionGratuitous Address Resolution Protocol Protection (GARP) prevents theIP Phone 2004 from GARP Spoof attacks on the network. In a GARP Spoofattack, a malicious device on the network takes over an IP address (usuallythe default gateway) by sending unsolicited (or Gratuitous) ARP messages,thus manipulating the ARP table of the victim’s machine. This allows themalicious device to launch a variety of attacks on the network, resulting inundesired traffic routing. For example, a GARP attack can convince thevictim machine that the malicious device is the default gateway. In thisscenario, all traffic from the victim’s machine flows through the maliciousdevice.To enable GARP Protection during configuration, refer to Procedure 18,“Installing an IP Phone 2004 for the first time using manual configuration”on page 110 or Procedure 18, “Installing an IP Phone 2004 for the first timeusing DHCP” on page 116.Extensible Authentication ProtocolExtensible Authentication Protocol (EAP) is a general protocol that fulfillsthe protocol requirements defined by 802.1x. For further information on802.1x, refer to Appendix C: “802.1x Port-based network access control” onpage 361.Reinstalling an IP Phone 2004You can reinstall an existing previously configured IP Phone 2004 on thesame system. For example, the IP Phone 2004 can be assigned to a new user(new TN) or to an existing user who moved to a new subnet by changing theTN of the IP Phone 2004.Procedure 22Changing the TN of an existing IP Phone 20041 Repower the IP Phone 2004.Note: During the reboot sequence of a previously configured IP Phone,the IP Phone 2004 displays the existing node number for approximatelyfive seconds.
