DNS Training

What is Covered in the Intro Course?

A brief overview of some of the introductory course topics to be covered:


Internet before DNS
DNS Design Requirements
Resource Records

DNS Records

The DNS Record Format
A and AAAA records
Structure and Data Records


Stub and Iterative Mode Resolvers
Recursive and Non-recursive Queries
The NXDOMAIN Response

Caching, TTL and Scalability

Delegation, the Key to Scalability
Zones and Domains
DNS Zone Records: The SOA Record, the Serial Number and the NS Record

Nameserver Roles

Authoritative Name Servers
Iterative Mode Resolvers (aka Recursive Name Servers)
Security Aspects and Threats
“Cache Poisoning”

Lab Exercises

Debugging tools (dig, drill, nslookup, others)
Configuration of an authoritative server
Delegation of sub-domain
Configuration and delegation of a reverse zone

Nameserver Setup

Unbound, NSD4, BIND9
Other Implementations
Differences, Pros and Cons

Nameserver Logging

What, when and why. Consequences
Configuration details
Query Logging. Alternatives

Introduction to DNSSEC

The Kaminsky Attack 2008
DNSSEC Validation (verification of signed DNS data)


Each course is presented by Johan Stenstam (Online) and Mark Elkins (In person). Lab exercises are conducted using Laptops running X Windows. Students will connect either via PuTTY (for Windows) or via SSH (Secure SHell) to their (virtual) DNS Servers which are running on a BSD (Unix) system. Students are encouraged to use their own Laptops and/or bring USB memory sticks to keep copies of their work.


Who should attend?

The intended audience for these courses would be network engineers, network and DNS administrators as well as managers, people working in IT strategy, IT consultants, IT Security or anyone who needs an understanding of DNS and the DNS role on the Internet.



Both the Intro and Advanced courses require fundamental knowledge about the Internet, TCP/IP and Unix/Linux. Experience with a Unix/Linux text editor such as vi or emacs and with the Unix/Linux file systems and basic shell/operating system commands is compulsory.

There is a free and paid course "Learn UNIX from scratch using simple and practical approach" on Udemy which you can use to familiarise yourself with Unix.

The Advanced course requires the student to have completed the Introductory course or to at least provide evidence of adequate experience in managing DNS Systems.


Next Course Dates

There are no current courses

Courses are usually held twice a year, around September and at the beginning of the year, late January to early February. Registration is open a month or so before each course. The courses are usually held in Johannesburg (Midrand) and Cape Town. There is an Intro course and an Advance course which alternate in these locations. In an ideal world, the Intro course is the first course of any training session, followed by the Advance Course.

Course Trainers

Johan Stenstam

Johan Stenstam has a degree in Engineering Physics from the Royal Institute of Technology in Stockholm, Sweden. He has been providing consulting and professional training services, primarily in the areas of DNS, DNS Security, DHCP, systems design, name and address space management for the past 25-years. Johan was previously the DNS Product Owner at Netnod and is currently employed as a DNS Expert at the .SE ccTLD Registry.

Mark Elkins

Mark Elkins was born and educated in the UK, where he attended Queen Mary College (London University) from 1979 to 1983. Mark has been working on Unix based computer systems for over 30-years and he moved to South Africa in 1984, where he later co-founded Domain Name Services (Pty) Ltd. Mark has been involved in local DNS training for over 10-years and he is a certified CCIE (Cisco Engineer).

Course Registration

Applications are subject to a R2000.00 refundable deposit on attendance. Applications will only be confirmed on receipt of the deposit. Applications will be closed once the total number of deposits have been received. Deposits of delegates that do not attend will be forfeited, and in turn donated to the ISPA Teachers Training Program.
We can only accept up to two people from any one organisation

Deposits may be paid by direct transfer into the DNS ZA bank account using the Booking Reference number as a reference.

Account Holder: Domain Name Services (Pty) Ltd
Bank: ABSA
Current Account: 4075011418
Branch code: 632005

Please email proof of payment to accounts@dns.net.za.

The training course starts at 09h00 and finishes at 17h00.

Documentation, refreshments and lunch will be provided.


Registration Form

Your full name (First and Last name)
SA ID or Passport Number
Your Company Name (or Private)
Your full street address
Intolerances or allergies?
Car Registration for Parking?
Your phone number in the international format '+27.115682800'
Your phone number in the international format '+27.115682800'
Your e-mail address - eg 'support@dns.net.za'

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