NCS490 Date Assigned: 11/03/14 Ronny L. Bull Due Date: 11/15/14

Transcription

1 DNS Lab Write-up Craig T. Ciulla NCS490 Date Assigned: 11/03/14 Ronny L. Bull Due Date: 11/15/14 Setup on Primary VM In this section, I installed and configured all necessary packages on my primary VM for use as a Master DNS Server. 1.) I began by installing the packages needed to run the primary VM as a DNS server. I did this with the command yum install bind bind-utils -y 2.) Following this, I began editing a file located at /etc/named.conf. I changed the basic template to reflect the configuration needed for the primary VM. This included configuring the named service to run the primary VM as a master DNS server with support for reverse DNS lookup, the ability to poll public DNS servers, and the location of the forward and reverse DNS library. It also included the setting of the master and slave IP addresses and the listing of the slave DNS as an alternative name server. 1

2 3.) Following this, I created the file /var/named/forward.ciullac referenced in line 44 of /etc/named.conf This is the file the named service uses to lookup logical addresses by name. The contents of the file are captured in the screenshot below: In this file I have the names ciullac-1 and masterdns associated with the IP address , and the names ciullac-2 and secondarydns associated to the address ) Following this, I created the file /var/named/reverse.ciullac referenced in line 49 of /etc/named.conf This is the file the named service uses to lookup names by logical addresses. The contents of the file are captured in the screenshot below: 2

3 Similar to how the forward.ciulla file was structured, this file contains IP addresses and associated them with their assigned names. 5.) With the main configuration files for the primary VM correctly setup, I used the command service named start to start the DNS service and begin running the primary VM as a Master DNS server. The service started without error, showing that there were no critical errors in the configuration files. Setup on Secondary VM 1.) Like with the primary VM, I began by installing the packages needed to run the secondary VM as a DNS server. I did this with the command yum install bind bind-utils -y 2.) Following this, I began editing a file located at /etc/named.conf. I changed the basic template to reflect the configuration needed for the secondary VM. This included configuring the named service to run the secondary VM as a slave DNS server with support for reverse DNS lookup, the ability to poll public DNS servers, and the location to store the forward and reverse DNS library. 3

4 I also set the secondary VM s IP address in this file 3.) With the main configuration files for the secondary VM correctly setup, I used the command service named start to start the DNS service and begin running the secondary VM as a Slave DNS server. The service started without error, showing that there were no critical errors in the configuration files. IPTABLES and Other Finishing Touches 1.) I began by looking up the ports which needed to be opened to receive DNS queries on the DNS servers. This ended up being port 43. Because of this I added this entry into the IPTABLES of both my machines for both TCP and UDP. I did this using the commands: iptabels -A INPUT -i eth0 -p udp -m udp dport 53 -j ACCEPT iptabels -A INPUT -i eth0 -p tcp -m tcp dport 53 -j ACCEPT 2.) With the IPTABLES configured correctly, I restarted the named service on both machines and checked the /var/named/slaves directory on the secondary VM to see if duplication correctly occurred. 4

5 As shown by the screenshot, the replication between machines was successful. This shows that the secondary VM is correctly running as a Slave DNS server. 3.) With replication correctly occurring, I configured the named service to start at the boot of both of the VMs. I did this using the command chkconfig named on 4.) Following this, I configured both VMs to use their own DNS server setup for name resolution. I did this my reconfiguring the /etc/resolv.conf file on both machines so that it referenced the IP addresses of the Master and Slave DNS servers. A screenshot of the file s contents is shown below: 4.) With the network information modified, I restarted the networking services on both machines using the command service network restart. I did this so that the changes would take effect and we could begin testing the DNS server s ability. 5

6 Testing 1.) I began my testing by pinging each VM by their names according to their DNS entries. I did this for every entry on both machines. 6

7 As shown by the screenshots, every test was successful. 2.) With the success of the first round of testing, I continued by looking up the IP of each entry using it s set name. Again, I did this from both VMs. 7

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9 As shown by the screenshots, these tests were successful as well. 3.) With all of the tests successful so far, I expanded my testing to include an address outside the network. 9

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11 With the success of the final test, the DNS server setup appears to be fully working. 11