How long do DNS changes take?

As long as the previous record time-to-live, not as long as the new one. Resolvers keep serving the old answer until their cached copy expires, which is why some people see the change immediately and others do not for hours.

What is the difference between an A record and a CNAME?

An A record points a name at an IP address. A CNAME points a name at another name, which is then resolved in turn. A CNAME cannot coexist with other records on the same name, which is why it cannot be used at the domain apex.

Why is my email not being delivered?

Check MX records first, then TXT. The frequent cause is two SPF records on one domain, which is invalid and can cause receivers to reject the mail outright. There must be exactly one, with all senders merged into it.

What are TXT records used for?

SPF, DKIM and DMARC for mail authentication, plus domain ownership verification for all sorts of services. They accumulate, and stale entries from services no longer in use are extremely common.

A DNS lookup that shows every record type at once

MXToolbox is the deeper tool and for mail problems specifically it is the one to use - blacklist checks and SMTP diagnostics have no equivalent here. For the ordinary question of what does DNS currently say about this domain, its shape gets in the way: one record type per lookup, with a results page selling you the next one.

Open the DNS Lookup →

MXToolbox and Softland, side by side

	MXToolbox	Softland
Record types per lookup	One at a time	A, AAAA, CNAME, MX, TXT and NS together
Blacklist and reputation checks	Extensive	Not offered
SMTP and mail flow diagnostics	Yes	Not offered
Account and monitoring	Available, and the point of the product	No account
Reading the result	Results page with adjacent offers	The records

The question is usually about the whole domain, not one record

When something is wrong with a domain, you rarely know which record is responsible. Mail is bouncing - that could be the MX records, or an SPF record in TXT, or a DKIM selector, or the domain resolving somewhere unexpected. The site is not loading - that could be A, AAAA, a CNAME pointing at something stale, or nameservers that were never updated at the registrar.

Looking at all of them together is how you find the one that is wrong, and it is usually obvious the moment they are side by side: a CNAME still pointing at the old host, an MX record for a provider you stopped using, two SPF records where there must only ever be one. Checking them individually means knowing the answer before you start.

What a lookup actually tells you, and what it does not

A public resolver answers from its cache. What you get back is what that resolver currently believes, which after a change may be the old value and may be the new one depending on how much of the previous time-to-live is left. That is why one person sees the new site and another sees the old one, and why both are correct.

So a lookup confirms what the public internet is being told right now. It does not confirm that your change is wrong, and it does not tell you how long the old answer will persist elsewhere - that is governed by the record time-to-live as it was before you changed it. Lowering the TTL a day before a migration is the standard trick, and it only works if you remember in advance.

TXT records are where the surprises live

TXT has become the place everything gets bolted on: SPF, DKIM selectors, DMARC policy, domain verification strings for a dozen services, and whatever a previous administrator added and never removed. It is also the record type with the most footguns, because several of the things stored there have rules about how many of them may exist.

The classic failure is two SPF records on one domain, which is invalid - receivers are entitled to treat it as a permanent error, and mail that was being delivered stops. It usually happens when a second service is added and its instructions are followed literally rather than merged into the existing record. Seeing every TXT record at once is how that gets spotted.

When MXToolbox is the better choice

You are diagnosing mail delivery and need blacklist checks, SMTP tests or a full mail flow trace.
You want continuous monitoring with alerts when a record changes, which is a product rather than a page.
You need record types outside the common set, or a lookup against a specific authoritative nameserver rather than a public resolver.

Frequently asked questions

How long do DNS changes take?: As long as the previous record time-to-live, not as long as the new one. Resolvers keep serving the old answer until their cached copy expires, which is why some people see the change immediately and others do not for hours.
What is the difference between an A record and a CNAME?: An A record points a name at an IP address. A CNAME points a name at another name, which is then resolved in turn. A CNAME cannot coexist with other records on the same name, which is why it cannot be used at the domain apex.
Why is my email not being delivered?: Check MX records first, then TXT. The frequent cause is two SPF records on one domain, which is invalid and can cause receivers to reject the mail outright. There must be exactly one, with all senders merged into it.
What are TXT records used for?: SPF, DKIM and DMARC for mail authentication, plus domain ownership verification for all sorts of services. They accumulate, and stale entries from services no longer in use are extremely common.

Try it yourself

Resolve a hostname to its records.

Open the DNS Lookup

MXToolbox is a trademark of its respective owner. Softland is not affiliated with, endorsed by or sponsored by MXToolbox. This comparison reflects how each product works rather than what either costs, because pricing and plan limits change; check MXToolbox’s own site for its current terms.