How to Check if a Domain Supports IPv6 (Website, Mail and DNS)
To check if a domain supports IPv6, look up its AAAA records for the website, the mail servers and the name servers. The IPv6 checker does this for up to 100 domains a run (500 after a free Google sign-in) and reports Website, Mail and DNS as Yes, Partly or No, with an overall IPv6 ready, Partly IPv6 or IPv4 only.
It is a DNS-only check. Nothing connects to the addresses it finds.
The by-hand way
- Look up the AAAA record of the domain and of
www. An IPv6 address back means the website side is covered. - Look up the MX records, then the AAAA record of each mail host.
- Look up the NS records, then the AAAA record of each name server.
- Repeat for every domain you manage.
You can do this with a DNS lookup, but one domain takes a handful of queries, and a portfolio takes hours. Our bulk DNS lookup shows raw records if you want to read them yourself.
Step 1: paste the domains
Paste one domain or a list, one per line. Addresses and URLs are trimmed to the domain. Up to 100 a run without an account, 500 after a free Google sign-in.
Step 2: run the check
A and AAAA records are looked up for the domain and www, up to three MX hosts and up to four name servers.
Step 3: read the three pills
| Pill | Yes means |
|---|---|
| Website | Both the domain and www have IPv6. Partly means only one does |
| Every checked MX host has IPv6 | |
| DNS | At least one name server has IPv6 |
The reasons list which host names lack IPv6, and any AAAA that is not a public address. Addresses such as ::1, link-local fe80::/10 or the documentation range 2001:db8::/32 cannot be reached from the internet, so they are listed separately and not counted.
Does IPv6 matter for email
For sending, yes. If a server sends over IPv6, it needs reverse DNS for that IPv6 address too. Check it with the reverse DNS lookup, and read IPv6 email sending requirements and checking the reverse DNS of MX servers.
What this check cannot do
- It is DNS only. It does not connect to the IPv6 addresses, so firewalls or broken routes do not show.
- It checks the domain and www only, up to three MX hosts and four name servers.
- It does not check reverse DNS for the IPv6 addresses.
- The limit is 100 domains a run without an account and 500 signed in.
Check the addresses you send to
IPv6 is one more thing that has to be right before mail is accepted; the address still has to exist. Upload your list on the verify page: the first 100 email checks are free with a Google sign-in, no card. Each address comes back valid, risky or invalid with a reason, and nothing is sent to anyone on the list. For larger or recurring lists, see bulk email verification, list cleaning and pricing.
Check your domains now
Paste them into the IPv6 checker.
Common questions
How do I check if a domain supports IPv6?
Look up its AAAA records. A domain is IPv6 ready for each service that has one: the website's host names, each mail server named in MX, and the name servers. An IPv6 checker does the lookups for many domains at once.
What is an AAAA record?
The DNS record that holds a host's IPv6 address, defined in RFC 3596. It is the IPv6 counterpart of the A record.
Does IPv6 matter for email?
For receiving, an MX host with an AAAA record lets IPv6-only senders deliver directly. For sending, Google's sender guidelines require every sending IP, IPv4 or IPv6, to have a PTR record that resolves back to it.
Can a missing AAAA record break my site?
Rarely. Most networks are dual-stack and fall back to IPv4. IPv6-only networks, which some mobile carriers run, rely on translation when it is missing.
Does the checker connect to the IPv6 addresses?
No. It reads DNS only, so a firewall or broken route would not show.
Check your list before you send
Real mailbox checks over SMTP, and nothing is sent to the address. Sign in with Google and your first 100 email checks are free, no card. Plans for bigger lists are on the pricing page.