Chapter 21 - Configuring The DHCP server
•Boot fi lename: The fi lename the cli ent sho uld req uest fr om a tf tp serv er
to boot from. This on ly app lies to network booted client s.
•Boot fi le serv er: The IP addr ess of t he tftp server to boot from. This on ly
applie s to ne twork b ooted cl ients.
•Server name: The host name of the bo ot serve r. Thi s only applies to
network booted client s.
•Lease length f or BOOT P client s: How long th e IP ass igned t o a BOO TP
client should be consi dered v alid.
•Lease end for BOOTP c lients: Cut of f date f or all BOOTP cl ient le ases.
•Dynami c DNS en abled: Should D NS infor mation be upda ted on t he DNS
server when a client receive s an IP address .
•Dynami c DNS do main na me: The domain name t o updat e dynam ic DNS
informa tion in .
•Dynami c DNS ho stname: Use th e speci fied ho stname for clie nts, or use
the hos tname supplie d by th e clien t.
•Dynami c DNS re verse d omain: The reve rser DN S domain to upd ate
dynami c inform ation i n for t he rever se DNS entry.
•Dynamic DNS reverse domain: The reverser DNS domain to update dynamic
information in for the reverse DNS entry.
Lesser used DHCP server configurations include
•Allow unknown clients : Shoul d DHCP accept request s from clients it has
never s een bef ore or only fr om clien ts that have a lready receive d lease s
in the past.
•Server is auth oritati ve: If the serv er is a uthorit ative, it will send d eny
messag es to a ny clien t which tries to rene w a lea se whi ch the server
knows the clie nt shou ldn't h ave.
•Option 82 Support.
Option 8 2 Support w ith Disabl e NAK
If DHCP relay clients (option 82 clients) are used on the same subnet as the DHCP
server, some clients will immediately try to renew a lease right after receiving it by
requesting a renewal directly from the DHCP server. Since the DHCP server is only
configured to provide that lease through a relay agent with the right option 82 fields
added, the server will send the client a NAK to disallow use of the lease. Enabling
this option disables this reject message, so that the renewal request that the DHCP
relay agent sends a moment later (which the DHCP server accepts since it has the
right option 82 fields added) will be the only message for which the client receives a
reply. If the DHCP server and clients are not on the same subnet, this option is not
required. The meaning of the value of many fields depends on the client's
interpretation of the field, so the actual meaning of a field is determined by the client.
See the documentation of the client to determine what values are required by the
client for special options.
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