What factors influence IP reputation?

IP reputation is built from the historical sending behavior associated with a specific server address. The key factors include:

Sending volume patterns showing consistent, predictable behavior versus sudden spikes. Complaint rates from recipients marking mail as spam. Bounce rates indicating list quality. Spamtrap hits signaling poor hygiene or purchased lists.

Blocklist appearances on lists like Spamhaus, Barracuda, or SORBS severely damage IP reputation. Authentication failures and content spam scores also contribute.

For shared IPs, reputation is collective. Your neighbors' behavior affects your deliverability even if your own sending is clean.

IP reputation is the inspection history of a specific vessel. Every port visit gets logged, and the accumulated record determines how quickly you clear customs at the next harbor.