IONOS at a Glance
| Type | Web hosting company |
|---|---|
| Website | www.ionos.com |
| Network (ASN) | AS8560 IONOS-AS |
| Announced IP space | 522 IPv4 prefixes (~899,072 addresses), 20 IPv6 prefixes |
| Customer nameservers | ns1045.ui-dns.com, ns1045.ui-dns.de, ns1045.ui-dns.org, ns1045.ui-dns.biz |
| Email (MX) | mx00.ionos.com, mx01.ionos.com |
| SPF include | include:_spf.perfora.net |
IONOS Nameservers
To host a domain with IONOS, set these as the domain's nameservers at your registrar. IONOS assigns nameservers per account; the pair below is an example of the format, and your exact pair is in the welcome email or control panel:
| Nameserver | IPv4 | Answered from network |
|---|---|---|
| ns1045.ui-dns.com | 185.132.34.45 | AS15418 Fasthosts Internet Limited |
| ns1045.ui-dns.de | 185.132.32.45 | AS15418 Fasthosts Internet Limited |
| ns1045.ui-dns.org | 185.132.35.45 | AS15418 Fasthosts Internet Limited |
| ns1045.ui-dns.biz | 185.132.33.45 | AS15418 Fasthosts Internet Limited |
- Log in to the registrar where you bought the domain and open its DNS or nameserver settings.
- Choose custom nameservers and replace the current ones with the IONOS nameservers above.
- Save, then wait: nameserver changes take up to 24–48 hours to spread. Follow it live with the DNS propagation checker or the NS lookup.
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IONOS IP Ranges and ASN
IONOS announces its address space from one autonomous system. Any website whose IP address falls in these ranges runs on IONOS's network. Counts are from the global routing table on September 25, 2026.
| ASN | Registered name | Registry | IPv4 prefixes | IPv4 addresses | IPv6 prefixes |
|---|---|---|---|---|---|
| AS8560 | IONOS-AS - IONOS SE, DE | ripencc · since 1997 | 522 | 899,072 | 20 |
Largest IONOS IP blocks
74.208.0.0/1682.165.0.0/1682.223.0.0/1687.106.0.0/16212.227.0.0/16217.160.0.0/1677.68.0.0/1785.215.128.0/172a0d:7f00::/292a02:2478::/29Look up any address in these blocks with the IP lookup or the ASN lookup.
IONOS Email DNS Records
If you use IONOS's own email service, these are the records your domain needs. Check them afterwards with the MX lookup and the SPF checker.
MX records
- 10 mx00.ionos.com (74.208.114.65)
- 20 mx01.ionos.com (74.208.114.66)
Priorities shown as a typical order; use the exact values from your IONOS dashboard.
SPF
Add include:_spf.perfora.net to your SPF record. It currently expands to:
v=spf1 ip4:74.208.4.192/26 ip4:82.165.159.128/27 -allHow to Check if a Website Is Hosted on IONOS
Enter the domain in the checker at the top of this page. It names IONOS when one or more of these signals match, and lists each one as evidence:
- The site's IP address is inside AS8560, the network IONOS announces.
- The domain uses IONOS nameservers (ui-dns.com, ui-dns.de, ui-dns.org, ui-dns.biz). This shows where DNS is managed, which is usually but not always the host.
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IONOS FAQ
What are IONOS's nameservers?
IONOS customers point their domain to ns1045.ui-dns.com, ns1045.ui-dns.de, ns1045.ui-dns.org, ns1045.ui-dns.biz. IONOS assigns the exact pair per account, so check your welcome email or control panel for yours. Changes take up to 24–48 hours to spread through DNS.
What is IONOS's ASN?
IONOS announces its IP addresses from AS8560 (IONOS-AS, registered with RIPENCC).
How many IP addresses does IONOS have?
As of September 25, 2026, IONOS's network announces 522 IPv4 prefixes covering about 899,072 IPv4 addresses, plus 20 IPv6 prefixes (source: RIPEstat routing data).
How can I tell if a website is hosted on IONOS?
Run the domain through the hosting checker on this page. It reports IONOS when the site's IP address is inside AS8560, the network IONOS announces, and it shows every matching signal as evidence.
Is IONOS a web host or a CDN?
IONOS is a web hosting company: it provides domains, shared and WordPress hosting, VPS and cloud servers and email.
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IONOS is a trademark of its owner. DNS Robot is not affiliated with IONOS unless an offer above is marked sponsored.