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IONOS Nameservers

IONOS gives each domain its own set of four on ui-dns.de, .biz, .org, and .com, such as ns1018.ui-dns.de. Your account lists yours; the check below reads them from your domain.

IONOS's own help pages · its nameservers asked directly · no log kept

IONOS's nameservers

A set of four per domainIONOS Anycast · AS15418
ns1ZZZ.ui-dns.dens1ZZZ.ui-dns.bizns1ZZZ.ui-dns.orgns1ZZZ.ui-dns.com

Yours are in your IONOS account: Menu > Domains & SSL > your domain > Name server tab. IONOS's guide

usercentrics.com, asked at three serversns1010.ui-dns.comNOERROR aans1127.ui-dns.deNOERROR aans-diy.ui-dns.comREFUSED

Any numbered IONOS server answers for any numbered zone; only the separate ns-diy set refuses. Still enter the four your account lists.

ns1ZZZ.ui-dns.de / .biz / .org / .comA set of four per domain

AsksIONOSns1ZZZ.ui-dns.de / .biz / .org / .com

No domain at hand? Try , a site at IONOS.

How to point a domain to IONOS's nameservers

Add the domain to your IONOS account first, then enter the names IONOS lists for it at the domain's registrar. Nothing is copied in the switch.

Your visitors keep reaching the old host until resolvers follow the new delegation.

Leaving IONOS? Add every record at the new host first, then change the nameservers, and keep IONOS's zone answering for the .com referral's 2 days.

The switch, in three placesIONOS's help pages · October 24, 2026

  1. 1At IONOS

    Set up the external domain: Menu > Domains & SSL > Set up external domain.

    Nothing is copied when the nameservers change: the zone at IONOS starts with what you add.

  2. 2At the domain's registrar

    Choose IONOS Name server; enter the four names from the Name server tab at the registrar.

    The highlighted part is your domain's own, from your IONOS account; these are usercentrics.com's.

  3. 3The wait: the .com registry

    Wait up to 72 hours: IONOS's figure before the domain works with its products.

    IONOS says72 hr
    .com referral TTL2 days

    “it may take up to 72 hours before you can use the external domain with your”

Bars: IONOS's own figure, and the NS TTL the .com registry gave out when we asked on October 24, 2026.

Is my domain's DNS at IONOS?

Ask any of IONOS's numbered servers, with recursion off: a zone it holds comes back with the aa flag and its SOA, whichever four numbers the domain was given. The separate ns-diy set answers REFUSED for it.

The check above does this at every IONOS server for your domain, then compares each record with what Google and Cloudflare hand out.

What IONOS's servers answereddig +norec +tcp · October 24, 2026
A zone it holdsusercentrics.comThe zone
$ dig @ns1093.ui-dns.com usercentrics.com SOA +norec +tcp
;; status: NOERROR · flags: qr aa
usercentrics.com. 86400 IN SOA ns1018.ui-dns.de. hostmaster.1and1.com. 2018042765 …
Its zone, asked at another setusercentrics.comNo zone
$ dig @ns-diy.ui-dns.com usercentrics.com SOA +norec +tcp
;; status: REFUSED · flags: qr (no aa)
;; ANSWER: 0, AUTHORITY: 0    ; NSID: 8560_de-kae-bs_diy
A domain it doesn't holdzq7x3k9p2m-dnsrobot-test…No zone
$ dig @ns1093.ui-dns.com zq7x3k9p2m-dnsrobot-test-20261024.com SOA +norec +tcp
;; status: REFUSED · flags: qr (no aa)
;; ANSWER: 0, AUTHORITY: 0    ; NSID: 15418_gb-lon-thn_customer-dns82

How each host says “no zone”

Recorded with dig over TCP, recursion off, on October 24, 2026.

What are IONOS's MX records?

IONOS Mail uses mx00.ionos.com and mx01.ionos.com as its MX records, and _spf-us.ionos.com as its SPF include.

They sit in the zone wherever the domain's DNS is hosted: change the nameservers without them and mail stops. What breaks in a move

The records to copyIONOS's help pages · October 24, 2026
IONOS MailIf it's missing
MXmx00.ionos.commx01.ionos.comIf it's missing: mail can't reach the mailboxes
TXTv=spf1 include:_spf-us.ionos.com ~allIf it's missing: its mail fails SPF checks

www.ionos.com

How to check if a website is hosted on IONOS

Look at the site's address, not its nameservers: IONOS's websites run on AS8560, while its nameservers answer from IONOS Anycast (AS15418).

So a domain can use IONOS's DNS and be hosted elsewhere, or the other way round. The Hosting Checker reads the address, nameservers, CNAME and headers together.

One domain, two networks: usercentrics.comTeam Cymru · October 24, 2026
usercentrics.com
NS
Nameserversns1018 / 1112 / 1108 / 1093.ui-dns.*AS15418 IONOS Anycast
A
Website141.193.213.20 · 141.193.213.21AS209242 Cloudflare London, LLCnot in IONOS's hosting networks: this site is hosted elsewhere

IONOS's address spaceRIPEstat · September 25, 2026

AS8560IONOS-AS

IONOS SE · RIPE NCC · since 1997

899,072

IPv4 addresses · 522 prefixes · 20 IPv6 prefixes
74.208.0.0/1682.165.0.0/1682.223.0.0/16
  • AddressAS8560
  • NS*.ui-dns.com/de/org/biz
  • CNAME—
  • Headersx-ws-origin
  • Check a site at IONOSHosting Checker
Routing data from RIPEstat, September 25, 2026; signals from the Hosting Checker's registry.

IONOS nameservers: FAQ

What are IONOS's nameservers?

IONOS gives each domain its own set of four nameservers on ui-dns.de, .biz, .org, and .com, such as ns1018.ui-dns.de. Your IONOS account lists the four for each domain, and the check on this page reads them from the domain's delegation. Any numbered IONOS server answers for any numbered zone; only the separate ns-diy set refuses. Still enter the four your account lists.

How do I change my nameservers to IONOS?

Set up the external domain: Menu > Domains & SSL > Set up external domain. Choose IONOS Name server; enter the four names from the Name server tab at the registrar. Wait up to 72 hours: IONOS's figure before the domain works with its products. Then check the zone with the tool on this page before you switch.

How long does a nameserver change to IONOS take?

IONOS says up to 72 hours. The real bound is the registry's NS TTL: the .com registry hands out a delegation for 2 days, so some resolvers keep asking the old nameservers that long. Keep the old host's zone answering until then, and compare both zones before deleting anything.

Can I use IONOS's DNS without its hosting?

Yes. Its DNS Standard serves a domain registered elsewhere without a transfer, free for the first year. Point the domain's nameservers to the ones IONOS gives you, then add the records your site and mail need, since the new zone starts empty. Check it on this page before you switch.

Does IONOS support DNSSEC?

Yes, on its own nameservers. DNSSEC needs the DNS Pro or Domain Guard add-on and a DNSSEC-capable extension; IONOS then adds the DS record itself. If the domain is registered elsewhere, its registrar has to publish the zone's DS record, or validating resolvers reject it. Turn DNSSEC off before you move the nameservers away from IONOS.

What are IONOS's MX records?

IONOS Mail uses mx00.ionos.com and mx01.ionos.com, with the SPF include _spf-us.ionos.com. They belong in the zone wherever the domain's DNS is hosted, so add them at the new host before you move the nameservers away from IONOS, or mail stops reaching the mailboxes.

Is a site hosted on IONOS if it uses IONOS's nameservers?

Not necessarily: nameservers say where the DNS is, not the website. IONOS's nameservers answer from IONOS Anycast (AS15418), while its web servers are on AS8560. Look up the site's address, or run the Hosting Checker, which matches the address, nameservers, CNAME and headers.

Why do IONOS nameservers have numbers like ns1018?

IONOS spreads its customers over numbered servers, so each domain gets four names of the form ns1ZZZ.ui-dns.de, .biz, .org and .com, often with four different numbers. Measured live, any numbered server answers for any numbered zone, but the separate ns-diy set doesn't. Copy the four names your account lists, and check the zone on this page.

Which MX and SPF records does IONOS mail use?

For IONOS.com customers, the MX records are mx00 and mx01.ionos.com, and with DNS hosted elsewhere the SPF record is v=spf1 include:_spf-us.ionos.com ~all. IONOS UK customers use mx00 and mx01.ionos.co.uk with include:_spf-eu.ionos.com instead. On IONOS's own nameservers, SPF is switched on by default.

Other hosts' nameservers

The 13 hosts this check asks, by how many of 4,000 sampled websites use their nameservers.

Sites on each host's nameservers4,000 sites, Tranco ranks 20,001–600,000
  1. GoDaddynsNN.domaincontrol.comA pair per account140
  2. Namecheapdns1 + dns2.registrar-servers.comSeveral sets43
  3. OVHcloudnsNN + dnsNN.ovh.netA pair per domain27
  4. Hostingername.dns-parking.comA pair per site19
  5. IONOSthis pagens1ZZZ.ui-dns.de / .biz / .org / .comA set of four per domain16
  6. SiteGroundns1 + ns2.siteground.net9
  7. DreamHostns1–3.dreamhost.com6
  8. HostGatornsN · cnsN.hostgator.comA pair per hosting plan4
  9. Bluehostns1 + ns2.bluehost.com3
  10. Hosting.comns1–4.stableserver.net3
  11. 20ins1–4.stackdns.com2
  12. Squarespaceconnect1 + connect2.squarespacedns.comSeveral sets2
  13. WixnsN.wixdns.netA pair per account1
Nameservers read through 1.1.1.1 for 4,000 random sites of the Tranco list; each row opens that host's page.

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