Dns

This scenario shows how to configure a DHCP client to receive information about a DNS server.

Test DNS Server

Description

DUT0 is configured to obtain some information over DHCP: IP address and DNS host.

Scenario

Step 1: Set the following configuration in DUT1:

set interfaces ethernet eth0 address 10.215.200.100/24
set service dhcp-server shared-network dhcpserver options authoritative
set service dhcp-server shared-network dhcpserver subnet 10.215.200.0/24 options default-router 10.215.200.100
set service dhcp-server shared-network dhcpserver subnet 10.215.200.0/24 start 10.215.200.50 stop 10.215.200.50
set service dhcp-server shared-network dhcpserver subnet 10.215.200.0/24 options dns-server 10.215.200.100
set service dns static host-name teldat.com inet 172.24.0.221
set service dns static host-name test1.teldat.com inet 172.24.0.225
set service dns static host-name dut1.teldat.com inet 10.215.200.100
set service dns forwarding logs

Step 2: Set the following configuration in DUT0:

set interfaces ethernet eth0 address dhcp
set service dns forwarding dhcp
set service dns forwarding logs

Step 3: Ping IP address 10.215.200.50 from DUT0:

admin@DUT0$ ping 10.215.200.50 count 1 size 56 timeout 1

Show output

PING 10.215.200.50 (10.215.200.50) 56(84) bytes of data.
64 bytes from 10.215.200.50: icmp_seq=1 ttl=64 time=0.027 ms

--- 10.215.200.50 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.027/0.027/0.027/0.000 ms

Step 4: Run command service dhcp-client show leases interface eth0 at DUT0 and check if output matches the following regular expressions:

DHCP server:\s+10.215.200.100
Subnet mask:\s+255.255.255.0
Routers:\s+10.215.200.100
Name-servers:\s+10.215.200.100

Show output

Interface:     eth0
IP address:    10.215.200.50
Subnet mask:   255.255.255.0
Routers:       10.215.200.100
Name-servers:  10.215.200.100
Domain-name:
NTP servers:
DHCP server:   10.215.200.100
Lease time:    43200
Expiry date:   Thu Jan 25 12:24:47 2024
Reason:        BOUND

Step 5: Run command interfaces ethernet eth0 show at DUT0 and check if output contains the following tokens:

10.215.200.50/24

Show output

-----------------------------------------------------------------
Name           IP Address           Admin  Oper  Vrf  Description
-----------------------------------------------------------------
eth0  10.215.200.50/24              up     up
      fe80::dcad:beff:feef:6c10/64

Step 6: Run command service dns forwarding show nameservers at DUT0 and check if output contains the following tokens:

10.215.200.100

Show output

-----------------------------------------------------
  Nameserver    Domain     Available Via     Priority
-----------------------------------------------------
10.215.200.100  *       DHCP interface eth0  5

Step 7: Run command nslookup teldat.com at DUT0 and check if output contains the following tokens:

172.24.0.221

Show output

Server:         127.0.0.1
Address:        127.0.0.1#53

Name:   teldat.com
Address: 172.24.0.221
** server can't find teldat.com: REFUSED

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