Apipa
Essay by review • December 21, 2010 • Study Guide • 329 Words (2 Pages) • 794 Views
Automatic Private IP Addressing feature in Windows DHCP processing that assigns a class B IP address in the 169.254.0.0 range to the client when a DHCP server is unavailable
While APIPA can automatically self-assign a TCP/IP address to a Windows 98 system, it does not generate all of the information typically provided by a DHCP server, such as DNS and WINS Server addresses. Therefore, a system relying on APIPA can only resolve domain and NetBIOS names via broadcasts. Currently, APIPA systems can only communicate with systems that also have an APIPA address.
APIPA is meant for non-routed environments, with usually less than 25 clients
Scenarios involving APIPA
a. Boot: No previous IP / No DHCP Server:
o - the system will do a Discover three times, if it cannot find the DHCP server, it will assign itself the Class B address
o - it will not show an error message
o - it will do a discover every three minutes
b. Boot: Previous IP / No DHCP Server:
o - the system will check for the DHCP server, if it cannot find one, it pings the default gateway
o - if the default gateway replies, then the system will keep the previous leased IP address
o - if it cannot find the default gateway, then it will assign itself an IP address
o - it will show an error message
o - it will do a discover every three minutes
o - if a DHCP server comes on line later, the user will get a dialog that states communication has been re-established with the DHCP server
c. Boot: Lease Expires / No DHCP Server:
o - system will try to reestablish the lease of the IP address
o - when no DHCP server is found, it will then assign itself an IP address
o - it will show an error message
o - it will do a discover every three minutes
o - if a DHCP
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