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THE UNIVERSITY OF BRITISH COLUMBIA Computer Science 317 Section !"1 #ui$ ! Fe%ru&r' !( !"1) In*tructor+ Norm Hutc,in*on

Time+ -) minute*

Tot&. m&r/*+ -"

T,i* 0ui$ con*i*t* o ( p&2e* inc.u4in2 t,i* co5er p&2e6 8,en in*tructe4 to 4o *o 5eri' t,&t 'ou ,&5e & comp.ete 0ui$ This is a closed book quiz. Notes, books, electronic devices or aids, or other materials are not allowed. Answer all the questions on this paper. Use the backs of pages if you need more space. e be sure to indicate that an answer is being continued on the back of a page. !ive short but precise answers. Always use point form where appropriate. "arks will be deducted for answers that ramble, repeat information, or contain information not relevant to the question. The marks for each question are given to the left of each question. Use this to manage your time. REA9 AN9 OBSERVE THE FOLLO8IN: RULES :OVERNIN: E;AMINATIONS+

#. $ach $ach candid candidate ate must must be be prepar prepared ed to produ produce, ce, upon upon reque request, st, a U%ca U%card rd for for identi identific ficati ation& on& '. %andidates %andidates are not not permitte permitted d to ask questi questions ons of the the invigil invigilators ators,, e(cept e(cept in cases of suppose supposed d errors errors or or ambiguities in e(amination questions. ). No candid candidate ate shall shall be permitt permitted ed to enter the e(amin e(amination ation room after after the e(pir e(piration ation of one*half one*half hour from the scheduled starting time, or to leave during the first half hour of the e(amination. +. %andidates %andidates suspected suspected of any any of the following following,, or similar, similar, dishonest dishonest practices practices shall shall be immediatel immediately y dismissed from the e(amination and shall be liable to disciplinary action -aving at the place of writing any books, papers, calculators, computers, sound or image  playersrecorderstransmitters  playersrecorderstransmitters /including /including telephones0, or other memory memory aid devices, other than those authorized by the e(aminers& 1peaking or communicating with other candidates& 2urposely e(posing written papers to the view of other candidates or imaging devices. The plea of accident or forgetfulness shall not be received. 3. %andidates %andidates must not destroy destroy or or mutilat mutilatee any e(aminati e(amination on materi material& al& must hand in all all e(amina e(amination tion papers& papers& and must not take any e(amination material from the e(amination room without permission of the invigilator. 4. %andidates %andidates must follow follow any any additio additional nal e(amin e(aminatio ation n rules rules or direction directionss communic communicated ated by the the instruc instructor tor or or invigilator. •

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Marks

A44ition&. Ru.e* &n4 9irection*+ You &re not permitted to ask questions o questions  o t,e in5i2i.&tor* 4urin2 t,e eoot name server, '0 ca nameserver )0 bc name server +0 gov name server and it could be responsible for the vs domain, if not there could be # more for the vs domain. 1o the answers are + if gov covers the vs domain or 3 if it doesnCt. /3 and 4 are acceptable provided one clearly indicates that the application is querying a local name na me server which then does the other queries0 ) points

 b0 After 3 minutes we again do a lookup of  ecos.vs.gov.bc.ca.  ecos.vs.gov.bc.ca. =hat is the most /reasonable0 number of GN1 servers we would need to query to resolve the address now; =hat is the least /reasonable0 number. %arefully 8ustify your answer. 9f the server has the name cached cache d then we will get it back immediately and the answer is 7 /# if local name server is identified0. 9f nothing is left in the cache then the most is 3 /40 based on o n the argument in #. ' points

c0 =hat =hat is is the the most most /re /reas ason onab able le00 numb number er of of name name ser server verss we woul would d now now need need to quer query y to res resol olve ve the address doonesbury.washingtonpost.com address doonesbury.washingtonpost.com whose cname is site.doonesbury.com is site.doonesbury.com.. /Heep in mind the caching rules in the questionCs preamble.0 %learly e(plain how the number was arrived at.

#0 root server server '0 com )0 washingtonpost at which point we get back a cname and have to look it up. 1o we need to do a lookup of site.doonesbury.com. =e donCt need to go to the root as we know where the com server is so +0 query to com GN1 30 query to doonesbury.com

Total is 3, /4 if you query your local server.0 ) points %21% )#? @uiz ' ebruary '4, '7#3 2age ) of 4 5 Norm -utchinson Not to %e copie4 u*e4 or re5i*e4 =it,out e