Linux DNS (BIND), DHCP and Servers

Transcription

1 it 8 Liux (B), HCP ad mail ervers oa Warre

2 HCP oa Warre

3 HCP ervice yamically assigs a P address to requestig machies P addresses are leased P addresses are leased scope of addresses ca be assiged or excluded from assigmet 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

4 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

5 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 addresses ca be excluded from the scope oa Warre

6 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

7 HCP Lease Process Cliet broadcast a lease request HCP server respods ad offers a P address oa Warre

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

9 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 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 dhcliet r -utility to allow a user to request a lease reewal dhcliet eth0 -utility to allow a user to request a lease be termiated oa Warre

10 B () oa Warre

11 ervice esolves FQ (fully qualified domai ames to P addresses tatic atabase usig host ames ( adid itterett coveti tio)) ames stored i i a text file Provide reverse lookup services Has sophisticated cachig techiques oa Warre

12 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 oa Warre

13 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

14 ame esolutio Process oa Warre

15 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

16 Zoes of uthority Zoe of uthority -Portio of ame space for which a particular ame server is resposible 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

17 esource ecord ypes -address record maps host ame to P address -maps host ame to Pv6 address CC -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 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 oa Warre

18 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 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 for which it is ot authoritative or cotais o delegatios oa Warre

19 slookup commad lie utility that allows troubleshootig for servers ytax ~]# slookup itt-tech.edu erver: ddress: #53 o-authoriative aswer: ame: itt-tech.edu ddress: oa Warre

20 edmail oa Warre

21 sedmail e of the mail servers available with ed Hat Liux ost commoly used P server used o the teret Files are located i the /etc/mail directory oa Warre

22 mail ervice o sed four compoets are eeded P server to sed the PP3 server to dowload the received mail to the users cliet user s cliet (eg. utlook or thuderbird to read the or a P (eg. evolutiio or mail) cliet to read the directly from the server user accout i the form of user@mydomai.com oa Warre

23 sedmail Compoets ail rasfer get Commoly referred to as the mail server Hadles distributig outgoig mail ad listes for icomig mail ail elivery get ccepts messages from the Copies the message ito a user s mailbox uses /usr/bi/procmail as the default - ail ser get u by the user to sed or read messages oa Warre

24 /etc/mail/sedmail.cf Cotais cofiguratio iformatio ad optioal values used to direct the behavior of the sedmail daemo ver 1000 lies i this file Good ews!! t will typically work without modificatio oa Warre

25 ailboxes comig messages will be processed ad stored i the /var/spool/mail directory ach file i the directory represets a valid user ame o the local machie ach idividual user s is set up to use this directory ad the user s accout ame as the icomig mailbox oa Warre

26 Popular mail Cliets Popular s iclude: utlook otes Lotus L etscape Composer udora ovecot Pie volutio oa Warre

27 stallig ad uig -ail se the followig commads to istall the ecessary compoets yum istall sedmail yum istall sedmail-cf yum istall squirrelmail yum istall dovecot oa Warre

28 essage torage comig messages will be processed ad stored i the /var/spool/mail directory ach file i the directory represets a valid user ame o the local machie. ach idividual user s is set up to use this directory ad the user s accout ame as the icomig mailbox for that user utgoig messages are stored i the /var/spool/mqueue directory oa Warre

29 Cofigurig sedmail /etc/sedmail.cf Cotais cofiguratio iformatio ad optioal values used to direct the behavior of the sedmail daemo ver 1000 lies i this file Good ews!! t will typically work without modificatio oa Warre

30 he.forward file he.forward file e way for users to redirect their ow mail Commo uses of the.forward file are: Pipig mail to a program to filter the mailbox cotets /usr/bi/procmail edig mail destied for oe user to aother mvegs@yahoo com List mail recipiets separated by a comma oa Warre

31 he aliases file llows you to use aliases address For example, all s set to ales could actually be received by a user his is a plai-text file. he etries are created usig this format: ales: root aria.veglia@mybox.com aria u ewaliases to commit chages made to this file oa Warre

32 PP/P services PP Post ffice Protocol P teret essage ccess Protocol Protocols used to fetch mail sed to receive mail from a remote server oa Warre

33 Lab 8 stall a HCP server stall a B server stall a server oa Warre