The Domain Name System (DNS) is often described as the phonebook of the Internet. Just as a contact list stores phone numbers, email addresses, and street locations for a person, DNS uses different record types to instruct browsers, mail servers, and game clients where to find specific services for a domain.
In this guide, we break down the most essential DNS record types used on Linux servers and RivinCloud VPS hosting.
1. Quick Reference Table
| Record Type | Purpose | Example Value |
|---|---|---|
| A | Maps hostname to an IPv4 address | 192.0.2.1 |
| AAAA | Maps hostname to an IPv6 address | 2001:0db8::1 |
| CNAME | Canonical Name / Alias pointing to another domain | cdn.example.com |
| MX | Mail Exchange server for receiving email | 10 mail.example.com |
| TXT | Arbitrary text (Domain verification, SPF, DKIM, DMARC) | v=spf1 include:_spf.google.com ~all |
| SRV | Service locator specifying custom ports and priorities | 0 5 25565 mc.example.com |
| NS | Nameserver record designating authoritative DNS servers | ns1.rivincloud.in |
| PTR | Reverse DNS mapping IP back to hostname | vps01.rivincloud.in |
2. Deep Dive into Record Types
1. A Record (Address)
The fundamental building block of the web. It translates a human-readable domain name directly into a 32-bit IPv4 address:
example.com. 300 IN A 192.0.2.50
2. AAAA Record (Quad-A)
Identical in function to the A record, but maps to a 128-bit IPv6 address:
example.com. 300 IN AAAA 2606:4700:4700::1111
3. CNAME Record (Canonical Name)
Acts as an alias pointing one domain name to another domain name (never directly to an IP).
blog.example.com. 300 IN CNAME myhostedblog.hashnode.network.
[!WARNING] According to RFC standards, a
CNAMEcannot coexist with other records on the root zone apex (@). UseCNAME FlatteningorALIASrecords if your provider supports it.
4. MX Record (Mail Exchange)
Tells email servers around the world where to deliver incoming emails addressed to @yourdomain.com. Includes a Priority number (lower number = higher priority):
example.com. 300 IN MX 10 aspmx.l.google.com.
example.com. 300 IN MX 20 alt1.aspmx.l.google.com.
5. TXT Record (Text)
Stores human and machine-readable text data. Heavily used for:
- Google / SSL Verification: Proving domain ownership.
- SPF (Sender Policy Framework): Preventing email spoofing.
- DKIM & DMARC: Cryptographic email authentication.
example.com. 300 IN TXT "v=spf1 mx include:_spf.google.com ~all"
6. SRV Record (Service Locator)
Allows protocols (like Minecraft, TeamSpeak, SIP, XMPP) to specify custom target ports and priorities without forcing users to type :25565:
_minecraft._tcp.play.example.com. 300 IN SRV 0 5 25565 mc.example.com.
3. Querying DNS Records from Linux Terminal
Inspect specific record types using dig:
# Query A record
dig +short A example.com
# Query MX record
dig +short MX example.com
# Query TXT records
dig +short TXT example.com
# Query SRV record
dig +short SRV _minecraft._tcp.play.example.com
Common Mistakes
- Pointing CNAME to an IP address: CNAME targets must be domain names (e.g.,
ghs.googlehosted.com), not raw IP addresses. - Missing trailing dot in BIND/Zone files: In raw zone files,
example.comwithout a trailing dot becomesexample.com.yourdomain.com.
Troubleshooting
- Email marked as spam? Check your
TXTrecords for missing SPF and DMARC configurations usingdig TXT yourdomain.com.
Best Practices
- Keep TTL values low (300 seconds) during server migrations so changes take effect rapidly.
- Always use SPF, DKIM, and DMARC
TXTrecords to ensure high email deliverability.
Frequently Asked Questions
What is the difference between an A record and a CNAME record?
An A record points a hostname directly to an IP address (192.0.2.1). A CNAME points a hostname to another hostname (alias.com -> target.com).
Conclusion
Understanding DNS record types allows you to route websites, configure business emails, and set up gaming servers effortlessly on your RivinCloud VPS!