Shared IP address with a bad reputation

What it means

Most people do not have their own sending server. Their email leaves from an IP address shared with many other customers of the same company: a web host, a newsletter tool, an email service.

Receivers judge the IP address as a whole. If one customer on it sends spam, the IP can get a bad reputation or a blacklist listing, and every customer on it is affected. These are your "bad neighbours".

Why it matters

• Your emails go to spam or are refused although you did nothing wrong.
• You cannot request removal yourself: only the IP's owner can fix the cause.
• Cheap shared web hosting is a common case: thousands of websites send through the same mail server, and some of them are hacked.

How to check

• Send a test email from the Delivmail home page. The "Sending infrastructure" section says whether the email came from a shared provider or your own server, and the blacklist section shows any listing of that IP. For shared providers Delivmail reduces the penalty, since the listing is rarely your fault.
• Look up the IP at /blacklists from time to time to see if the listing stays.
• If your emails are also failing SPF or DKIM, fix that first: it is often the real cause.

How to fix it

1. Check your own account first. Make sure you are not the bad neighbour: no hacked mailbox, no abused website form, no unexpected sent emails.
2. Contact your provider's support. Give them the IP address, the blacklist names and your Delivmail report. Ask them to fix the abuse or move your account to a clean IP or IP pool.
3. Stop sending through weak servers. If your website sends email straight from your web host, make it send through your mailbox provider or a reputable email service with an SMTP plugin or API.
4. Change provider if listings keep coming back. Large providers watch their IPs closely and remove abusers quickly.
5. Consider a dedicated IP only if you send large volumes regularly (tens of thousands of emails a month). A new dedicated IP has no reputation yet and must be warmed up slowly; with low volumes a good shared IP is often better.

Make your domain your strongest asset

Big receivers like Gmail rely more and more on the reputation of your domain, not only the IP. With SPF, DKIM and DMARC passing for your own domain, your good sending history follows you even on a shared IP, and when you change provider.

Tips

• Keep your list clean and your complaint rate low; it protects your domain reputation.
• Note the date when problems started; it helps the provider find the cause.

Check that it is fixed

Look up the IP again at /blacklists, then send a new test email from the home page. The blacklist section should be clean, or your emails should now leave from a different, clean IP.