TXT records and generic DNS text data

1. TXT Records

This row in your DNSprobe report prints the raw TXT records for the domain, usually as a simple table with host, type, value and TTL.

Why this matters

Seeing the exact TXT contents makes it easier to confirm that you entered verification tokens correctly, that there is only one copy of each policy and that nothing unexpected is still published.

How DNSprobe shows it

DNSprobe sends standard DNS queries for TXT records and displays the answers in the same way a resolver would see them, including quotes and any multiple strings returned by the server.

Typical issues you may notice here

• Old TXT entries left in place for services or providers you no longer use.
• Typos in verification tokens or policy strings compared to what the provider expects.
• Multiple unrelated TXT records squeezed on the same host, making troubleshooting harder.

Good practices for TXT records

• Regularly review TXT data at the apex and at well-known hosts to remove obsolete entries.
• Keep a short internal documentation of which service owns which TXT record.
• Avoid copying values by hand if the provider offers a copy-paste button or automatic DNS setup.

2. Common uses of TXT records

Many modern DNS-based features are implemented using TXT records that follow their own mini-syntax.

Examples of common TXT usages

• Domain verification for services such as search engines, analytics, cloud providers or SaaS platforms.
• E-mail-related policies and metadata (for example SPF, DMARC or reporting addresses).
• Service-specific configuration flags such as cloud storage ownership or code-hosting verification.
• Custom, internal-use text like notes or tracking identifiers used by your own tooling.

Each of these features defines its own syntax inside the TXT value. DNSprobe does not change the text; it simply surfaces what your zone currently advertises.

3. Where TXT records live: hosts and prefixes

TXT records can be attached to the root of the zone or to specific subdomains, often using a leading underscore to avoid collisions with real hostnames.

Typical TXT hostnames

• TXT at the zone apex (example.com) for global policies or site-wide verification.
• TXT on underscored names such as _acme-challenge.example.com or _service.example.com used by automated tools.
• TXT on dedicated subdomains such as mail.example.com or api.example.com for service-specific metadata.

Best practices for TXT hostnames

• Prefer the hostnames suggested by your provider; they are chosen to avoid conflicts with other records.
• Avoid piling many unrelated TXT uses onto the exact same host when you can separate them cleanly.
• Be consistent in naming conventions so that future administrators can recognise what each TXT record is for.

4. TXT value format and quoting

TXT values are stored as one or more quoted strings. DNS itself does not impose a key=value syntax, but many applications do.

Things to know about TXT formatting

• DNS servers may split a long TXT value into multiple quoted strings; resolvers join them back into a single logical value.
• Special characters such as spaces, semicolons or equals signs are allowed but must remain inside the quotes.
• Most modern policies use simple ASCII; if you paste Unicode characters, your DNS software may escape or reject them.

Best practices for TXT values

• Copy TXT values exactly as provided by the service, including quotes when your DNS interface expects them.
• Avoid hand-wrapping or reformatting values, as extra spaces or line breaks may change their meaning.
• When debugging, compare what DNSprobe shows with the provider’s documentation to spot subtle formatting errors.

5. TXT record size and multiple strings

TXT data is subject to size limits, both per string and per DNS response. Very long policies may be split across multiple segments.

Size limits in practice

Each TXT string is typically limited to 255 characters, but a TXT record may contain several strings that are concatenated by resolvers. The full DNS response must also fit within normal UDP or TCP limits.

Best practices for TXT length

• Keep TXT values as compact as possible while staying clear and standards-compliant.
• If a provider suggests reducing mechanisms or removing unused options to shrink a TXT value, follow their guidance.
• Be aware that very long TXT records can be harder to maintain and more fragile across different DNS control panels.

6. TTL choices for TXT records

The TTL of a TXT record controls how long resolvers cache its value before asking your nameservers again.

Why TTL matters for TXT

Short TTLs let you change verification tokens or service configuration quickly, but they generate more DNS traffic. Long TTLs reduce load but make changes slower to propagate.

Best practices for TXT TTLs

• Use shorter TTLs temporarily while you are deploying or debugging a new TXT-based feature.
• Once stable, increase TTLs to a reasonable value (for example one hour or more) to reduce unnecessary queries.
• When rotating keys or policies, plan ahead to avoid long periods where caches still hold the previous TXT value.

7. Test TXT records manually from your own terminal

DNSprobe lists all TXT records it finds for your domain (such as SPF policies, verification tokens and service-specific keys). You can reproduce the same checks yourself from a terminal by querying TXT records directly.

Linux: using dig (BIND utilities)

On most Linux distributions, the dig command is provided by the BIND utilities package. The following commands query all TXT records at the root of your domain. You can then optionally narrow the output to your SPF policy only:

                dig example.com TXT
                dig example.com TXT +short
    
                # Optional: filter the output to show only the SPF record    
                dig example.com TXT | grep "v=spf1"
        

macOS: using dig from the built-in tools

macOS ships with dig as part of its standard command-line tools. Open Terminal and run the same commands as on Linux to list all TXT records for your domain, then optionally filter the SPF record:

                dig example.com TXT
                dig example.com TXT +short
    
                # Optional: filter the output to show only the SPF record    
                dig example.com TXT | grep "v=spf1"
        

Windows: using nslookup

On Windows, the legacy nslookup tool can query TXT records for your domain. Run the following commands from a Command Prompt or PowerShell window to list TXT records for the root, or for a specific host if needed:

                nslookup -type=TXT example.com
    
                REM Optional: query TXT records for a specific host name instead of the root    
                nslookup -type=TXT sub.example.com
        

Important: only query DNS records for domains that you own or are authorised to analyse. Repeated automated lookups against third-party domains may be treated as abusive traffic by some providers.