IP Blacklisting

Understanding email blacklists and how to maintain a clean sending reputation.

What is IP Blacklisting?

IP blacklists (also called DNSBLs or RBLs) are databases of IP addresses known to send spam. Email providers like Gmail, Outlook, and Yahoo check these lists when receiving emails. If your sending IP appears on a blacklist, your emails may be blocked or sent to spam.

How waveMail Protects You

waveMail actively monitors sending IP reputation and takes several measures to keep your deliverability high:

  • Dedicated IP management — depending on your plan, you may have a shared or dedicated sending IP. Dedicated IPs give you full control over your reputation.
  • Automatic bounce processing — hard bounces are automatically blacklisted to prevent repeat sends to invalid addresses
  • Complaint monitoring — spam complaints are processed in real time, and persistent complainers are automatically unsubscribed
  • Sending throttling — emails are sent at rates optimised for deliverability, not just speed

Checking Blacklist Status

If you suspect deliverability issues, you can check your sending IP against major blacklists:

  1. Contact waveMail support to identify your sending IP
  2. Use free tools like MXToolbox Blacklist Check to scan your IP
  3. If listed, waveMail support can assist with the delisting process

Preventing Blacklisting

  • Always use double opt-in — this ensures you're only emailing people who genuinely want to hear from you
  • Never buy email lists — purchased lists contain spam traps and uninterested recipients
  • Clean your lists regularly — use Email Verification to remove invalid addresses
  • Honour unsubscribes promptly — waveMail handles this automatically, but never re-add someone who unsubscribed
  • Authenticate your domain — set up SPF, DKIM, and DMARC via Domain Management
  • Monitor your bounce rates — aim for under 2% hard bounce rate per campaign
  • Watch your complaint rate — aim for under 0.1% complaint rate

Email Blacklist (Global Suppression)

Within waveMail, the Email Blacklist is a global suppression list. Addresses on this list will never receive emails from any of your campaigns, regardless of which list they're on.

Addresses are automatically added to the blacklist when:

  • An email hard bounces (permanent delivery failure)
  • A recipient marks your email as spam
  • You manually blacklist an address

To view or manage the global blacklist, go to Email Blacklist in the sidebar.