Blocklisted IPs FAQ

Learn about delisting your blocklisted OVHcloud IPs.

Introduction

Blocklisting, also known as blacklisting, is a spam-fighting tool used on IPs (or IP ranges) to block email that is considered spam or may contain malware. If an email domain or IP address is blocklisted, emails from that domain or IP address may not reach their client - impacting deliverability and sender reputation. Emails that do go through may go to the recipient's spam folder rather than their inbox.

It is important to note that blocklists can include domains and IPs that are not threats to users and that some spam filtering services take reverse DNS into account when evaluating IP addresses, such as RATSspam.

Supported

• Spamhaus Block List (SBL)

  This is for newly purchased IPs.

  If the IP is listed under the Spamhaus Blocklist (SBL), you will need to submit a ticket to OVHcloud US Customer Support. Support will contact our Abuse Team, who will then contact the Internet Service Provider.

• eXploits Block List (XBL) or CSS

  If your IP is listed under eXploits Blocklist (XBL) and/or CSS Blocklist (CSS), it is due to configuration issues. Please follow the steps mentioned on the Spamhaus site to delist the IP. See the example below. Once you have followed the steps, you can delist it yourself.

  Example:

  

  

• Spamcop

• Barracuda

• SpamRATS

  To delist an IP from SpamRATS, the first and most important step is to configure reverse DNS (rDNS). Without a valid rDNS, the UP cannot be removed from the blocklist, especially for "Worst Offender" alerts.

  Step 1 - Configure rDNS

  Use your external domain registrar to create an A record that maps the domain name to your server's IP address (e.g., Domain: mail.example.com).

  Configure the PTR (rDNS) record using the OVHcloud Control Panel (instructions) or OVHcloud API (instructions).

  Use the command below or an online tool like MXToolBoox to verify the rDNS is set up correctly.

  dig -x <IP_ADDRESS>

  Good rDNS example output:

  {{;; ANSWER SECTION:
  1.2.0.192.in-addr.arpa. 300 IN PTR mail.example.com.}}

  The IP 192.0.2.1 resolves to mail.example.com, showing a valid reverse DNS configuration.

  Bad rDNS example output:

  {{;; ANSWER SECTION: (missing)
  ;; status: NXDOMAIN}}

  No PTR record exists for 203.0.113.1, as indicated by the missing ANSWER SECTION and status: NXDOMAIN.

  Step 2 - Delist an IP

  Use the SpamRATS Lookup Tool to check if the IP is listed.

  Request delisting from basic blocklists using the SpamRATS Removal Form.

  Request delisting from Worst Offender Alerts using the SpamRATS Contact Form and include:

  1. Evidence of a valid rDNS configuration (e.g., dig -x output).
  2. An explanation of the IP's history, ownership, and intended use.

  Best practices:

  Always configure rDNS by setting up an A record at your domain registrar using the OVHcloud Control Panel (instructions) or OVHcloud API (instructions).

  By following these steps, you can ensure proper reverse DNS setup and successfully delist your IP from SpamRATS.

Unsupported

s5h.net

curl -4 http://www.usenix.org.uk/content/rblremove

telnet www.usenix.org.uk 80
GET /content/rblremove HTTP/1.1
Host: www.usenix.org.uk
# press enter twice

UCEprotect

Fabel Spamsources

MIPSpace

Go further

For more information and tutorials, please see our other Dedicated Servers support guides or explore the guides for other OVHcloud products and services.