EXERCISES

1
EXERCISES

• Registration and address asignment
• DNS management
• Eugenie Staicut ltestaicut_at_linkguide.ici.ro
• Research Institute for Informatics
• Bucharest, Romania
• CEENet 97 3-rd Network Technology Workshop
• 23-31 August 1997, Zagreb, Croatia

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• All the PCs have WINDOWS95 and Debian Linux. If
  you are using WINDOWS, shutdown WINDOWS, then
  choose Debian Linux while rebooting the system.
• Login with username root, password CEENet97
• Exercise 1 Some tools for network debugging
• Display the TCP ports netstat -a more
• Display the routing table netstat -rn or
  netstat -r
• Use ping ping sun1.workshop.carnet
  .hr
• (use CTRL/C to stop)
• ping ftp.univie.ac.at
• Use traceroute traceroute www.ibm.com
• traceroute www.cisco.com
• Display the ARP table arp -a

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Exercise 2. Access the Internic and RIPE database

• telnet info.ripe.net ftp//ftp.rs.internic.net/
• ftp//ftp.ripe.net/ gopher//rs.internic.net/
• http//www.ripe.net/ http//www.internic.net/
• gopher//gopher.ripe.net/ telnet rs.internic.net
  
• You can make these additional exercises during
  your free time.
• Query the RIPE Databe
• whois -h whois.ripe.net help gthelp.ripe
• whois -h whois.ripe.net AS1755
• whois -h whois.ripe.net 161.53.0.0
• whois.h whois.ripe.net at
• whois -h whois.ripe.net ltpersongt

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Exercise 3. Checking DNS using host

• host !you will get the help informationhost
  lthost addressgt ! you will get IP address for
  lthostnamegt host sun1.workshop.carnet.hr
• host ftp.univie.ac.at
• host www.microsoft.com
• host ltip-addressgt ! you will get name for
  ltip-addressgt
• host 161.53.74.11
• host 131.130.1.72
• host 207.68.137.65
• host -t lttypegt ltquerygt ! query for a specific
  type of records (NS, SOA, MX, A, CNAME,
  PTR)
• host -t ns workshop.carnet.hr host -t soa
  workshop.carnet.hr
• host -a ltdomaingt !query for all record of a
  domain, verbose mode host -a carnet.hr host -a
  hr. Host -a workshop.carnet.hrhost -l a
  ltdomaingt !list all the zone for a domain host -l
  -a workshop.carnet.hrCheck other domains, which
  are known to you!

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Exercise 4. Checking DNS using nslookup(dig is
also available for another alternative)

• nslookup commandsserver ltnameservergt set
  the server to be queriedset type NS
  queries NS resourcesset type SOA
  queries SOA resourcesset type A
  queries A resourcesset type MX
  queries MX resourcesset type CNAME
  queries CNAME resourcesset type PTR
  queries PTR resourcesset type ANY
  queries ANY resourcesls ltdomaingt
  lists the ltdomaingt zonels ltdomaingt gt
  ltfile-namegt gets the zone ltdomaingt into the
  
• fileltfile-namegtview ltfile-namegt
  views the ltfile-namegt file
• nslookup
• gtset typeany
• gtworkshop.carnet.hr.
• gtcarnet.hr.
• gthr.
• gtls workshop.carnet.hr gt file1
• gtview file1 You can check
  other domains, known to you.

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Exercise 5. Setting up DNS servers

• Network address161.53.74
• domain workshop.carnet.hr
• We will set up 5 domains beneath the domain
  workshop.carnet.hr
• org-a.workshop.carnet.hr
• org-b.workshop.carnet.hr
• org-c.workshop.carnet.hr
• org-d.workshop.carnet.hr
• org-e.workshop.carnet.hr
• Each domain corresponds to the computers on a row
  and contains 4 hosts with
• the IP host part given by the following table
• host1 host2 host3 host4 Example
• org-e 217 218 219 220 host2.org-c.workshop.carnet
  .hr
• org-d 213 214 215 216 has the IP number
• org-c 209 210 211 212 161.53.74.210
• org-b 205 206 207 208
• org-a 201 202 203 204

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Exercise 5. Setting up DNS servers (continue)

• org-a.workshop.carnet.hr
• primary nameserver hos3.org-a.workshop.carne
  t.hr (161.53.74.203)
• secondary nameserver host3.org-b.workshop.carnet
  .hr (161.53.74.207)
• secondary nameserver host3.org-e.workshop.carnet
  .hr (161.53.74.219)
• hosts in the domain
• host1 161.53.74.201 host3 161.53.74.203
• host2 161.53.74.202 host4 161.53.74.204
• org-b.workshop.carnet.hr
• primary nameserver hos3.org-b.workshop.carne
  t.hr (161.53.74.207)
• secondary nameserver host3.org-c.workshop.carnet
  .hr (161.53.74.211)
• secondary nameserver host3.org-a.workshop.carnet
  .hr (161.53.74.201)
• hosts in the domain
• host1 161.53.74.205 host3 161.53.74.207
• host2 161.53.74.206 host4 161.53.74.208

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Exercise 5. Setting up DNS servers (continue)

• org-c.workshop.carnet.hr
• primary nameserver hos3.org-c.workshop.carne
  t.hr (161.53.74.211)
• secondary nameserver host3.org-d.workshop.carnet
  .hr (161.53.74.215)
• secondary nameserver host3.org-b.workshop.carnet
  .hr (161.53.74.207)
• hosts in the domain
• host1 161.53.74.209 host3 161.53.74.211
• host2 161.53.74.210 host4 161.53.74.212
• org-d.workshop.carnet.hr
• primary nameserver hos3.org-d.workshop.carne
  t.hr (161.53.74.215)
• secondary nameserver host3.org-e.workshop.carnet
  .hr (161.53.74.219)
• secondary nameserver host3.org-c.workshop.carnet
  .hr (161.53.74.211)
• hosts in the domain
• host1 161.53.74.213 host3 161.53.74.215
• host2 161.53.74.214 host4 161.53.74.216

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Exercise 5. Setting up DNS servers (continue)

• org-e.workshop.carnet.hr
• primary nameserver hos3.org-e.workshop.carne
  t.hr (161.53.74.219)
• secondary nameserver host3.org-a.workshop.carnet
  .hr (161.53.74.203)
• secondary nameserver host3.org-d.workshop.carnet
  .hr (161.53.74.215)
• hosts in the domain
• host1 161.53.74.217 host3 161.53.74.219
• host2 161.53.74.218 host4 161.53.74.220

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Examples of configuration files for DNS set up

• The process named runs on each PC
• Please have a look in the following files using
  the ?more ltfilegt? command
• /etc/resolv.conf - resolver configuration file
• /etc/named.boot - nameserver configuration file
• /var/named/named.root - defines the root servers
• (This file is available at ftp//ftp.rs.interni
  c.net/domain/named.root)
• /var/named/named.local - defines the IP for the
  localhost
• /var/named/named.rev-local - defines the reverse
  name for 127.0.0.1
• The example is given for host3.org-a.workshop.carn
  et.hr. The procedure is the same for the other
  nameservers, but replace org-a with org-b, org-c,
  etc.
• cd /var/named !change to the directory
  /var/named
• cp org-x.zone org-a.zone !copy the sample
  file org-x.zone to org-a.zone
• pico org-a.zone !using the pico editor mofify
  appropriately the file
• add the following lines to the file
  /etc/named.boot (using pico)
• primary org-a.workshop.carnet.hr.
  org-a.zone
• secondary org-b.workshop.carnet.hr 161.53.74.207
  org-b-sec.zone
• secondary org-e.workshop.carnet.hr 161.53.74.219
  org-e-sec.zone
• kill -HUP cat /usr/run/named.pid ! Restart
  the named process

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• Exercise 6. Checking your DNS server (your domain
  and the neighboring ones)
• Check the domain org-a.workshop.carnet.hr using
  nslookup
• !Check the primary nameserver host3.org-a.workshop
  .carnet.hr
• gtserver host3.org-a.workshop.carnet.hr
• gtset typeNS
• gtorg-a.workshop.carnet.hr
• gt ls org-a.workshop.carnet.hr
• !Check the secondary nameserver
  host3.org-b.workshop.carnet.hr
• gtserver host3.org-b.workshop.carnet.hr
• gtorg-a.workshop.carnet.hr
• gt ls org-a.workshop.carnet.hr
• !Check the secondary nameserver
  host3.org-e.workshop.carnet.hr
• gtserver host3.org-e.workshop.carnet.hr
• gtorg-a.workshop.carnet.hr
• gt ls org-a.workshop.carnet.hr
• Try telnet, ftp to host1.org-a.workshop.carnet.hr,
  and to host2, host3, host4

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• Exercise 6. Checking your DNS server (your domain
  and the neighboring ones) - continue
• Check the domain org-b.workshop.carnet.hr using
  host
• !Check the primary nameserver host3.org-b.workshop
  .carnet.hr
• host -t NS org-b.org-b.workshop.carnet.hr
  host3.org-a.workshop.carnet.hr
• host -l -a org-b.org-b.workshop.carnet.hr
  host3.org-a.workshop.carnet.hr
• !Check the secondary nameserver
  host3.org-c.workshop.carnet.hr
• host -t NS org-b.org-b.workshop.carnet.hr
  host3.org-c.workshop.carnet.hr
• host -l -a org-b.org-b.workshop.carnet.hr
  host3.org-c.workshop.carnet.hr
• !Check the secondary nameserver
  host3.org-a.workshop.carnet.hr
• host -t NS org-b.org-b.workshop.carnet.hr
  host3.org-a.workshop.carnet.hr
• host -l -a org-b.org-b.workshop.carnet.hr
  host3.org-a.workshop.carnet.hr
• Try telnet, ftp to host1.org-b.workshop.carnet.hr,
  and to host2, host3, host4

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Adding a new entry within a domain

• Suppose that in each domain we want to add
• a host name www which points to the host
  sun1.workshop.carnet.hr.
• a host name ftp which points to
  host1.org-i.workshop.carnet.hr. (ia,.e)
• Do the following
• Using the pico program edit the zone file
  org-i.zone for your domain
• increase the serial number
• add the records
• www IN CNAME sun1.workshop.carnet.hr.
• ftp IN CNAME host1.org-i.workshop.carnet.hr.
• Restart the named process kill -HUP cat
  /var/run/named.pid
• Check your configuration
• Use nslookup or host program
• Test http//www.org-i.workshop.carnet.hr
• Test ftp//ftp.org-I.workshop.carnet.hr