Master DNS vocabulary: record types (A, AAAA, CNAME, MX, TXT, NS, SRV), TTL, DNS propagation, authoritative vs. recursive resolvers, and DNSSEC.
0 / 10 completed
1 / 10
What is the difference between an authoritative DNS server and a recursive resolver?
Authoritative servers are the source of truth for a DNS zone — they return definitive answers. Recursive resolvers (like 8.8.8.8) walk the DNS hierarchy on a client's behalf, caching results to speed up future lookups.
2 / 10
A CNAME record in DNS is used to:
CNAME (Canonical Name) creates an alias — e.g., www.example.com → example.com. All record types are then looked up against the canonical name. CNAMEs cannot coexist with other record types at the same node (the 'CNAME at apex' problem).
3 / 10
TTL (Time To Live) on a DNS record controls:
TTL is measured in seconds. A low TTL (e.g., 60s) means changes propagate quickly but generate more query load. A high TTL (e.g., 86400s = 1 day) reduces load but slows propagation — important to lower TTL before planned DNS changes.
4 / 10
DNSSEC protects DNS by:
DNSSEC uses public-key cryptography to sign zone data. Resolvers validate the chain of trust from the root zone down to the record. DNSSEC prevents cache poisoning attacks (Kaminsky attack) but does not encrypt queries — that is the role of DNS over HTTPS (DoH) or DNS over TLS (DoT).
5 / 10
An SRV record in DNS is primarily used to:
SRV records encode the protocol, service name, priority, weight, port, and target hostname — for example, _sip._tcp.example.com. They are used by SIP, XMPP, Kubernetes service discovery, and other protocols so clients can find service endpoints dynamically.
6 / 10
Reviewer: 'I'm seeing a dig command in the comment that's trying to resolve our API domain. Shouldn't we be using DNS resolution internally? It seems like unnecessary complexity.'
What does this reviewer *most* likely mean when referring to 'DNS resolution'?
The reviewer is referring to the process of a DNS server translating a human-readable domain name (like api.example.com) into an IP address. This is core to how applications connect to services over the internet and is what 'DNS resolution' fundamentally describes – it's not just about reachability, but obtaining that crucial mapping.
7 / 10
Sarah (DevOps): 'Okay team, we're experiencing intermittent issues with our new microservice. Logs show it's failing to connect when trying to resolve the auth-service.internal domain. I suspect a misconfigured DNS record.'
What is Sarah *likely* referring to when she mentions a 'misconfigured DNS record'?
Sarah is focusing on the DNS aspect because domain names are resolved via DNS records. A 'misconfiguration' here means that the DNS record associated with auth-service.internal isn't correctly set up – perhaps it points to a nonexistent server or an outdated IP address, causing the connection failure.
8 / 10
PR Description: 'Updated DNS configuration for the new staging environment. Changed the TTL on the www.staging.example.com record to 600 seconds. This allows for faster propagation of changes during testing.'
What is the primary purpose of adjusting the TTL (Time To Live) value on a DNS record?
TTL is a crucial setting that dictates how long DNS resolvers (like your browser's) will store a copy of the DNS record. A shorter TTL means changes propagate faster, but also increases query load; a longer TTL reduces query load but delays updates.
9 / 10
David (Dev): 'Just finished deploying the new version of our service. We're using DNS records to point to the new servers. I've set up a CNAME record for api.newservice.com that points to api.oldservice.com.'
What is the *main* benefit of using a CNAME record in this scenario?
CNAME records create an alias – they point one domain name (api.newservice.com) to another (api.oldservice.com). This is particularly useful when you need a simple way to redirect traffic and allows the underlying IP address of api.oldservice.com to be updated without changing the DNS record itself.
10 / 10
Reviewer: 'I noticed you're using a dig +trace command in your script. That's good for debugging, but it's not ideal for production. It can slow things down significantly.'
What is the reviewer *most* concerned about when they criticize the use of a dig +trace command?
While dig +trace is useful for debugging, it performs a recursive DNS query chain – repeatedly querying different servers to find the authoritative source of information. This can be incredibly slow and consume significant network bandwidth, especially in production environments where performance matters.
Master DNS vocabulary: record types (A, AAAA, CNAME, MX, TXT, NS, SRV), TTL, DNS propagation, authoritative vs. recursive resolvers, and DNSSEC.
Is this exercise free to use?
Yes. Every exercise on CoderSlingo, including this one, is free to use with no account, sign-up, or paywall.
How many questions are in "DNS Vocabulary"?
This exercise has 10 questions. Each one gives instant feedback with an explanation, so you can see exactly why an answer is right or wrong.
Do I need to create an account to save my progress?
No account is required. The progress bar and score are tracked in your browser for the current session -- the exercise is designed to be a quick, repeatable drill rather than something you resume later.
What happens if I get an answer wrong?
You'll see the correct answer highlighted immediately, along with a short explanation of why it's correct. Wrong answers aren't penalized beyond your score, and you can keep going through every question.
How is this exercise different from reading an article?
Articles explain vocabulary and concepts through prose, while exercises like this one are interactive drills -- multiple-choice questions -- that test and reinforce your recall of specific terms and phrasing.
Can I retry this exercise?
Yes -- use the "Try again" button on the results screen to reset your score and go through all the questions again from the start.
Where can I find more Networking Language exercises?
Browse the full Networking Language hub for related drills, or check the site-wide exercises index for other IT English topics.
Is this exercise suitable for beginners?
This exercise assumes basic familiarity with IT terminology. If a term feels unfamiliar, check the site Glossary for a plain-English definition before attempting the questions.
How often is new content like this published?
New exercises are added regularly across all categories, alongside new vocabulary sets and articles. Check back on the exercises hub to see what's new.