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Network Services - Lab 6 - DNS part II

TODO - tell about the DNSSEC time sink and how to avoid it.

Activity Zero - VM setup

• LambSauce
  • CentOS
  • Primary for myco
  • On bench machine 1, the 71 network.
  • IP: 10.150.71.2
• Wisdom
  • Windows Server
  • Secondary for myco
  • On bench machine 2, the 72 network.
  • IP: 10.150.72.2

More VMS will be added later, throughout the lab.

Activity 1 - Make Wisdom a Primary for theirco

1.1

The instructions go through this step-by-step - However, there are some clarifications:

• Step L
  • Use theirco instead of myco
  • Use any IP on your second network that does not cause conflicts.

1.2

Add the appropriate variant of the following to /etc/named.conf

zone "theirco.abc1234.com" {
	type slave;
	file "slaves/theirco.abc1234.com";
	masters{
		10.150.72.2;
	};
};

The instructions imply that something needs to be added to the options section. This is false.

My option section contains only directory "/var/named"; and not even that is needed.

1.3

The instructions here are incomplete and inefficient. Perform these steps:

• systemctl stop named
• rm -rf /var/named/slaves/
• start a wireshark capture
• systemctl start named
• When the transfer has appeared, stop wireshark and save.
• Have the wireshark open for the signoff.

Convert the binary file to text with the following command, replacing abc1234 where needed:

named-compilezone -f raw -F text -o /var/named/slaves/theirco.abc1234.com.dns theirco.abc1234.com /var/named/slaves/theirco.abc1234.com

• -f raw specifies the input is raw
• -F text specifies to create an output file in text
• -o (filename) is where to create the output file
• The FQDN is specified
• The final argument is the file to read

Finally, cat /var/named/slaves/theirco.abc1234.com.dns

Signoff 1

• Have the wireshark of the transfer open
• Have the text zone file open

Activity 2

2.1

Here we’re creating another CentOS-BIND-DNS stack to serve a subdomain.

The instructions have been using subnets

Create new VM

On bench machine 1 (the 71 network for me), Full-clone the base CentOS_7.3 VM.

The instructions will call it CentOS2.

I will call it LOOOP.

Configure Networking

Use the GUI to set the ip information. I placed LOOOP on 71.100

Update YUM:

yum clean all
yum --disablerepo=\* --enablerepo=base,extras,updates update

Set the Hostname:

hostnamectl set-hostname [name]

Disable SELinux:

1. vim /etc/selinux/config
2. set SELINUX=permissive
3. restart with shutdown -r now

Verify changes with sestatus

Install BIND:

yum -y install bind bind-utils
firewall-cmd --zone=public --permanent --add-service=dns

Configure bind

vim /etc/named.conf

options{
	directory "/var/named";
};
zone "mgmt.myco.abc1234.com" IN{
	type master;
	file "mgmt.myco.abc1234.com.dns";
};
# Reverse zone here.

Create Zone files.

The mgmt domain needs two fake entries. Almost everything needed can be copy/pasted from CentOS1, or LambSauce in my case.

Note on the reverse lookup file.

I don’t have subnets, so whichever server is set as DNS for a host will be the one they ask for reverse lookup.

fin

• named-checkconf
• named-checkzone

If both check commands are fine, and it starts, and systemctl status named -l looks okay, then it’s probably okay.

2.2 - Make sure it’s okay.

This section has two parts

Table

While the report does ask for a DNS topology, nothing needs to be done In Lab to create this, as long as you have notes somewhere of what VMs do what job.

Network Traces

Report question 3.1 asks about these network traces. You need two:

• A client asking CentOS1 about a host in mgmt
  • This fails, because CentOS1 doesn’t know about mgmt
• A client asking CentOS2 about a host in mgmt
  • This should work

This is where I got in my second lab section.

Informal, extra notes

How long did this take me?

My first lab session was less productive than expected, due to a number of things I had to fix from lab5 and errors in the lab6 instructions. I hope those following my notes fare better.

Session	Time Spent	Progress
In Lab, Nov 19th	2 Hours	Activity 1, signoff 1.
Lab Nov26th	2 hours	Through 2.2, no signoff