L I N U X. Unit 6 S Y S T E M DHCP & DNS (BIND) A D M I N I S T R A T I O n DPW

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1 it 6 HCP & (B) oa Warre

2 HCP ervice yamically assigs a P address to requestig machies P addresses are leased scope of addresses ca be assiged or excluded from assigmet HCP servers do ot talk to each other ll machies except the HCP server ca be assiged P ddresses dyamically. oa Warre

3 dvatages of HCP educes the admiistrative workload ad elimiates clerical errors llows admiistrators to easily chage P cofiguratios cales well to both small ad huge etworks utomates the etire process of P address maagemet oa Warre

4 HCP copes HCP server ca maage cliets o more tha oe subet cope - he rage (or pool) of cliet P addresses o a etwork or subet that will be maaged by a HCP server scope is limited to oe subet ad the P address must be cotiguous pecific addresses or rages of addresses ca be excluded from the scope oa Warre

5 ulticast copes Class addresses that rage from to for use i P multicastig hese addresses are used for multicastig oly ad ot for regular HCP scope. group of CP/P host computers share the multicast P address he P datagram is forwarded to all members of the multicast group Zero or more hosts are idetified by the multicast address he membership of a multicast group is dyamic so Hosts ca joi or leave the group at ay time oa Warre

6 HCP Lease Process Cliet broadcast a lease request Cliet HCP server respods ad offers a P address Cliet HCP iscover HCP ffer erver erver oa Warre

7 HCP Lease Process Cliet broadcasts a acceptace message HCP equest Cliet erver HCP server ackowledges the lease assigmet Cliet hese are the oly two frames required to reew a address HCP CK erver oa Warre

8 HCP Lease eewal he default lease period is 8 days HCP cliet will sed a lease reewal request to the issuig HCP server to reew it s lease after 50% of the lease period expires f o respose is received after 87.5% of the lease has expired, the cliet will broadcast to ay HCP server for lease reewal ifcofig eth0 /reew - utility to allow a user to request a lease reewal ipfofig eth0 /release - utility to allow a user to request a lease be termiated oa Warre

9 oa Warre

10 ervice esolves FQ (fully qualified domai ames to P addresses tatic atabase usig host ames ( ad iteret covetio) ames stored i i a text file ca be cofigured to use W etbios ame resolutio although W is beig phased out Provide reverse lookup services Has sophisticated cachig techiques oa Warre

11 Host ames ll CP/P commuicatio is based o P addresses ach computer o a etwork has at least oe etwork iterface, which is called a host, ad each host has a P address that is uique o that etwork very datagram trasmitted by a CP/P system cotais the P address of the sedig computer ad the P address of the iteded recipiet Whe users access a shared folder o the etwork or a Web site o the teret, they do so by specifyig or selectig a host ame, ot a P address ames are much easier to remember ad use tha P addresses oa Warre

12 Host Files For CP/P systems to use these friedly host ames, they must have some way to discover the P address associated with a specific ame the early days of CP/P etworkig, each computer had a list of ames ad their equivalet P addresses, called a host table t that time, there were few eough computers o the fledglig teret for the maiteace ad distributio of a sigle host table to be practical oa Warre

13 amespaces amespace is a hierarchical, tree-structured list of host ames, startig at a uamed root that is used for all operatios ach domai ca have additioal child domais oa Warre

14 amespaces he amespace has a hierarchical structure ad each domai ame is uique withi a amespace t the top of the teret amespace is the root domai. he root domai is represeted by. (a period) oa Warre

15 ame esolutio Process oa Warre

16 Zoes Primary Zoes store the database locally ad have authority for the data ecodary Zoes get the zoe iformatio from aother server Forward lookup zoes allow a resolver (a applicatio icluded i web browsers ad most FP software) to obtai a P address whe the host ame is kow everse lookup zoe allows a resolver to obtai a host ame whe a P address is kow. he P record ca be automatically created whe you eter a record ito the Forward lookup zoe oa Warre

17 Zoes of uthority Zoe of uthority - Portio of ame space for which a particular ame server is resposible Zoe trasfer - Process of dowloadig zoe data from a master ame server to a secodary ame server : a sigle server ca be authoritative for multiple zoes oa Warre

18 tadard Primary Zoe stadard primary zoe hosts a read/write copy of the zoe i which resource records are created ad maaged ly oe server ca host ad load the master copy of the zoe o additioal primary servers for the zoe are permitted, ad oly the server hostig the primary zoe is allowed to accept dyamic updates ad process zoe chages oa Warre

19 tadard ecodary Zoe copy of the zoe file may be stored o oe or more servers to balace etwork load, provide fault tolerace, or avoid forcig queries across a slow, wide area etwork (W) lik his stadard secodary zoe is a read-oly copy of the stadard primary zoe formatio from a primary zoe is trasmitted to a secodary zoe by performig a zoe trasfer, which is doe by copyig the zoe file from the primary server to a secodary server oa Warre

20 esource ecord ypes - address record maps host ame to P address - maps host ame to Pv6 address C - caoical ame record establishes a alias for a host ame - mail exchage record idetifies a mail server for a specified domai - ame server record idetifies the ame server for a specified domai H - multihomed computer oa Warre

21 esource ecord ypes P - poiter record associates a P address with a host ame i a reverse lookup database - start of authority specifies the domai for which the server is resposible W - W record idetifies the W server to be cosulted to resolve ames ot recorded i ame space V idetifies servers that provide specific services oa Warre

22 oot Hits servers resolve queries usig local authoritative or cached data But if the server does ot cotai the requested data ad is ot authoritative for the ame i a query, it may perform recursive resolutio or retur a referral to aother server depedig o whether the cliet requested recursio he erver service must be cofigured with root hits to resolve queries for ames that it is ot authoritative for or for which it cotais o delegatios oa Warre

23 slookup tility commad lie utility that allows troubleshootig for servers ytax c> slookup microsoft.com erver: s02.plfld01.j.comcast.et ddress: o-uthorative aswer ame: microsoft.com ddresses: oa Warre

24 ample oa Warre

25 Lab 6 Cofigure a HCP ad (B) rver oa Warre