How to check if you are listed in the Kundenserver?
- DNS Lookup: If your IP is
1.2.3.4, you can query:nslookup 4.3.2.1.exitnodes.tor.dnsbl.sectoor.de. If it returns127.0.0.1, your IP is listed as an active Tor exit node. - As the official website doesn’t provide a way to check, we suggest using third‑party tools such as MXToolbox to confirm your status.
How to remove a Domain/IP address from Kundenserver?
- To request a delisting from Kundenserver Relays, which is an internal RBL used by IONOS (1&1) to block detected open relays, you must follow the manual removal process through their postmaster service.
- Direct Email Support: Email the IONOS email security team directly at postmaster@ionos.com
- Fix before requesting: Delisting requests submitted without fixing the core problem will result in immediate re-listing.
- The Blacklisted IP Address. Confirmation that you have closed the open relay on your server.
- Automated Re-testing: IONOS systems may automatically re-test your IP. If the relay is closed, the listing can sometimes expire within 24–72 hours.
- Manual Review: Manual requests via the postmaster team typically take 24 to 48 hours to process.