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4.0 Network Services and Security

DNS Record Types Practice Questions

New in CCNA v2.0

Diagnosing A, AAAA, CNAME, MX, NS, and PTR records for host, web, and mail access by name.

CCNA v2.0 objective 4.4 · objective map

Author-reviewed by LabFabric · 25 September 2026 · Report a content issue

One solved question, so you can see how these are marked

Which DNS record type maps a hostname to an IPv6 address?

AAAA

An A record returns an IPv4 address and an AAAA record returns an IPv6 address. PTR is used for reverse lookups and NS names the zone's name servers.

Every question in the set below is marked like this. The answers stay hidden until you pick one.

Find related practice in the CCNA path
All 9 DNS Record Types questions in this set

Answers and explanations appear when you work through the set above.

  1. A web server should answer to both www.example.com and shop.example.com, which are aliases for host web1.example.com. Which record type creates an alias?

    • CNAME
    • MX
    • NS
    • PTR

  2. Users can browse to a company site by name, but external senders report that email to the domain is not delivered. The A record is correct. Which record should be checked?

    • MX
    • PTR
    • CNAME for www
    • AAAA for www

  3. An MX record has the value '10 mail1.example.com' and another has '20 mail2.example.com'. Which server does a sender try first?

    • mail1.example.com, because the lower preference value is preferred
    • mail2.example.com, because the higher value is preferred
    • Both at once, because the values are equal weight
    • Neither, because MX records must contain IP addresses

  4. Which record type identifies the authoritative name servers for a DNS zone?

    • NS
    • A
    • MX
    • CNAME

  5. Which record type is used for a reverse lookup that returns a hostname for the IPv4 address 192.0.2.10?

    • PTR
    • A
    • AAAA
    • NS

  6. A user can ping a server at 203.0.113.25 successfully but cannot ping its name, server.example.com. What is the most likely problem?

    • Name resolution, such as a wrong DNS server address or a missing record
    • A duplex mismatch on the switch port
    • A missing default route on the server
    • A blocked TCP port 22

  7. Which command queries a mail exchanger record for example.com using nslookup?

    • nslookup -type=MX example.com
    • nslookup -mail example.com
    • nslookup /mx example.com
    • nslookup smtp example.com -ptr

  8. A host has IPv6 connectivity and both A and AAAA records exist for a site, but the AAAA record points to an address that is not reachable. What symptom is likely?

    • Delays or failures reaching the site, because the client may try the IPv6 address first
    • The site loads faster because IPv6 is always preferred
    • The DNS server stops answering queries
    • The client's IPv4 address is removed

  9. Which IOS command sets the DNS server a router uses to resolve names?

    • ip name-server 192.0.2.53
    • ip dns server 192.0.2.53
    • dns-server 192.0.2.53
    • ip host-server 192.0.2.53