Glossary
IP reputation
IP reputation is how much mailbox providers and blocklists trust the IP address your email comes from, based on its history of spam complaints, bounces, spam trap hits, volume and authentication. Poor IP reputation sends mail to spam or gets it blocked.
What Is IP Reputation?
In short Every mail server connects from an IP address, and receivers keep their own record of what came from it: how much, how steadily, how often recipients complained and how many messages went to unknown users.
Public blocklists such as the Spamhaus Blocklist (SBL) list IP addresses identified as malicious, and many receivers check them before they accept a connection.
On a shared IP, such as Google Workspace, Microsoft 365 or an email service provider's shared pool, you share the record. Google's sender guidelines say the activity of any sender on a shared IP affects the reputation of all senders on it. On a dedicated IP you own the reputation, so you also have to warm it up and keep volume steady.
IP Reputation Example
Example: a company moves from a shared pool to a new dedicated IP and sends 50,000 emails on the first day. Outlook.com starts deferring its mail, and the team cuts back to 2,000 a day and raises volume over four weeks while the IP builds a history.
IP Reputation in Practice
For cold email sent from Google or Microsoft mailboxes, you don't control the IP. Your domain and mailbox behavior carry more weight: authentication, complaint rate, bounce rate and steady volume.
FAQ
What is IP reputation?
The trust mailbox providers and blocklists place in the IP address your mail comes from, based on that IP's sending history. Good reputation helps mail reach the inbox. Poor reputation gets it filtered or blocked.
How do I check my IP reputation?
Look the IP up in Spamhaus's free reputation checker. If you own the IP, register it with Microsoft's Smart Network Data Services (SNDS) to see Outlook.com's data on it. If you send from Google Workspace or Microsoft 365, the IPs belong to the provider, so watch your domain instead.
What is the difference between IP reputation and domain reputation?
IP reputation belongs to the address a server sends from. Domain reputation belongs to the domain in your From address, DKIM signature and links, and it follows you to any IP or provider. Senders on shared IPs mostly build domain reputation.
How do you fix a bad IP reputation?
Find the cause first: a bad list, a compromised account or a sudden volume spike. Fix it, request removal from any blocklist that lists the IP, then cut volume and send only to engaged recipients while the record improves.
Should you use a shared or dedicated IP for cold email?
Ken's view: send cold email from Google Workspace or Microsoft 365 mailboxes on the provider's shared IPs. A dedicated IP only pays off at steady high volume, and then every problem on it is yours.
Do This in Ken
Do This in Ken
Delivery provisions Google and Microsoft mailboxes, so you send from provider-managed IPs, and enrolls new Google Workspace mailboxes in warmup automatically. Your part is the domain: clean lists and steady volume.
- Module
- Delivery
- Open in Ken
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The new Ken opens to the waiting list in batches.
Related
- GTM Glossary
Every GTM term, grouped by topic.
- Sender reputation
- PTR record
- Email warmup
- Google Postmaster Tools
- Email bounce rate
- Ken
Sources
| Source | Checked |
|---|---|
| Google: Email sender guidelines | |
| Spamhaus: Spamhaus Blocklist (SBL) | |
| Microsoft: Smart Network Data Services (SNDS) |
Changelog
- Page published.