Shared IP reputation for mail

On shared hosting, many accounts send mail from the same outbound IP addresses, so IP reputation is shared across those accounts. You stay welcome by authenticating with SPF, DKIM, and DMARC, and by keeping bulk campaigns off the same path as everyday transactional mail. A compromised form on a neighboring account can hurt the shared IP, and we respond when that happens. You do not need a dedicated IP for normal mail; clean auth on shared is enough for receipts and password resets.

Check listings before you redesign the template

If messages land in junk, look up the sending IP on the blocklists that major receivers still use. When the IP is clean, the problem is usually the template, the content, or missing authentication. Redesigning headers while you are listed will not fix delivery. If you are listed, open a ticket with the IP and the list name. We already monitor shared outbound mail, so a neighbor incident is a different conversation from a newsletter that simply looks like bulk mail.

Authenticate first, then separate campaigns

Set SPF, DKIM, and DMARC so they align for your domain. That sequence is how you stay welcome on a shared IP. After auth is solid, decide whether large blasts belong on the same server as password resets and order receipts. Sending a product launch to tens of thousands of purchased addresses on that IP can drag transactional mail into a reputation it did not earn. Use an ESP for campaigns; keep receipts and account mail on hosting.

Avoid “reputation booster” services that demand a permanent SPF include you cannot explain. You may inherit their other customers and make delivery worse. Only add includes you understand and control.

After an incident on the shared IP

Rotate passwords on mailboxes used by contact forms. Review outbound mail for the account and disable any plugin that was sending without permission. Leave your auth records in place. Pause campaigns on the box until the IP is no longer listed. Then send wanted mail slowly—messages people expect and reply to. Raw volume is not a warmup. Authenticated mail that recipients want is what rebuilds trust.

Work in this order: check lists, fix auth headers, split campaign mail from transactional mail, and only then discuss IP options. Jumping straight to a dedicated IP because one Gmail user junked a reset often means you buy an IP and keep the same broken template.