An email blacklist (also called a blocklist) is a list of IP addresses or domains that have been seen sending spam. When a receiving mail server finds your server's IP or your domain on a list it trusts, your mail is rejected or sent to spam. This guide explains how blacklists work, how to check whether you are listed, what to do about it, and what is different when you send from shared hosting.
Blacklists record IP addresses and domains that have sent spam, and mail providers use them to reject or filter mail. Check a listing with MXToolbox or the list's own lookup, find and fix the cause (usually a hacked mailbox, a compromised website script or a bad mailing list), then request delisting. On Domain India shared hosting the sending IP belongs to the server, so delisting a shared server IP is done by our support team: open a ticket with the report.
1. How blacklists work
Blocklist operators run spam traps (addresses that never sign up for anything), collect complaint data and watch sending patterns. When an IP address or domain sends mail that trips their rules, they add it to their list. Mail servers around the world then query those lists, often through DNS, while accepting mail.
What happens next depends on the receiving server. Some reject the message outright with a bounce that names the list; others accept it but score it as spam. So a listing can show up either as bounces or as mail quietly landing in junk folders.
2. Common reasons for a listing
- A compromised mailbox. Someone has the password and is sending spam through your account. This is the most common cause.
- A hacked website. A malicious script on the site sends mail directly, or a contact form is abused to send spam.
- Bad lists. Mail to bought, rented or very old lists hits spam traps and invalid addresses.
- High complaint or bounce rates. Recipients marking your mail as spam, or many addresses that no longer exist.
- Missing authentication. No SPF, DKIM or DMARC makes your mail easier to forge and harder to trust.
3. Check whether you are listed
- Find the sending IP.Open a message you sent, view its headers (in Gmail: the three-dot menu, then Show original) and look at the
Receivedlines. Or ask support for your server's outgoing IP. - Run a blacklist check.MXToolbox's blacklist check tests an IP or domain against many lists at once. MultiRBL is another multi-list lookup.
- Read any bounce message.A rejection usually names the list and often includes a link explaining why.
- Check the list itself.Use the list's own lookup page, such as Spamhaus's, to see the reason and the removal steps.
Not every list matters equally. A listing on a widely used list such as Spamhaus affects delivery to many providers; a listing on a small or little-used list may affect almost nobody. Some lists charge for fast removal; you do not need to pay a list operator to fix real delivery problems, so focus on the lists your recipients actually use.
4. What to do if you are listed
- Find the cause first.Check sent folders and mail logs for mail you did not send, look for new or changed files in your website, and review who has mailbox passwords. Delisting before you fix the cause just leads to a new listing.
- Stop the source.Change the password of any compromised mailbox, remove malicious scripts, protect contact forms with a CAPTCHA, and stop sending to the problem list.
- Fix authentication.Make sure SPF, DKIM and DMARC are in place and passing (section 6).
- Request delisting.For your own dedicated IP or your domain, follow the list's removal process and say what you fixed. Many lists also expire entries automatically once the spam stops.
- Watch for relisting.Check again over the next few days and keep an eye on bounces.
On Domain India shared hosting, mail leaves from the server's IP address, which other accounts share. You cannot request delisting of a shared server IP yourself. If a check shows the server IP listed, open a ticket with the report or the bounce message, and our support team will investigate and handle the delisting. Support cannot change a shared hosting account's IP address; if you need your own IP, that means a VPS.
If the cause was a hacked website, clean it before anything else. The hacked-site checklist walks you through it.
5. Keep your sending clean
- Send only to people who asked. Use double opt-in for newsletters and remove addresses that bounce.
- Make unsubscribing easy. Gmail and Yahoo require bulk senders to offer one-click unsubscribe and to keep spam complaints low.
- Use a newsletter service for campaigns. Shared hosting is not built for bulk mail: outgoing mail is limited to 200 messages per hour per account on Domain India cPanel servers and 1,000 per day on DirectAdmin. See Do you limit the amount of mail I can send.
- Protect every mailbox. Use strong, unique passwords and change them if you ever see mail you did not send.
- Protect forms. Contact forms without a CAPTCHA are a common route for spam.
6. Authentication: SPF, DKIM and DMARC
Gmail, Yahoo and Outlook.com now expect senders to authenticate their mail, and bulk senders must have all three records.
| Record | What it proves | Where it lives |
|---|---|---|
| SPF | Which servers may send mail for your domain | One TXT record on your domain starting v=spf1 |
| DKIM | The message was signed by your domain and not changed | A TXT record at selector._domainkey.yourdomain.com |
| DMARC | What receivers should do when SPF and DKIM fail, and where to send reports | A TXT record at _dmarc.yourdomain.com |
A domain may have only one SPF record. If you also send through a newsletter service, merge it into the same record, for example v=spf1 +a +mx include:your-newsletter-service ~all, using the include your service documents. Start DMARC in monitoring mode with v=DMARC1; p=none; rua=mailto:[email protected], read the reports, then tighten it.
On cPanel, Email › Email Deliverability checks SPF and DKIM and shows the correct records; DKIM is on by default for new cPanel accounts. On DirectAdmin, DKIM uses the selector x. The full walk-through is in Email deliverability deep-dive: SPF, DKIM, DMARC and BIMI and Setting up DMARC.
7. Monitor your reputation
- Google Postmaster Tools shows spam rates and authentication results for mail your domain sends to Gmail, once you send enough volume.
- Microsoft's sender tools give similar data for Outlook.com recipients if you send in volume.
- Test regularly. Send a message to a scoring service such as mail-tester.com, which also checks common blocklists; see How to test email deliverability for your own website.
- Watch your bounces. A sudden rise in rejections is often the first sign of a listing.
8. Not a blacklist: blocked by the server firewall
If you suddenly cannot reach your website, control panel or mailbox from your office, but it works on mobile data, your own IP has probably been blocked by the server firewall after repeated failed logins, often from an old saved password in a mail app. That is not an email blacklist. See How to identify if CSF has blocked your IP and how to fix it.
9. Where Domain India fits
Every Domain India shared hosting plan includes mailboxes on your domain, and support handles delisting for our shared server IPs. If you want business mail kept separate from your website hosting, Business Email signs every message with DKIM and provides the SPF and DMARC records for your domain. The price on the card is live and excludes 18% GST.
- Priced per mailbox - start with one
- Email at your own domain ([email protected])
- Add and remove mailboxes yourself
- Webmail with calendar, contacts and tasks
Support is on 24/7 live chat, and tickets get a first response within 15 minutes; resolution can take longer depending on the issue. There is no phone support.
Frequently asked questions
What is an email blacklist?
An email blacklist, or blocklist, is a list of IP addresses or domains seen sending spam. Receiving mail servers check these lists and may reject or filter mail from anything listed.
How do I check if my domain or IP is blacklisted?
Find your sending IP in the Received headers of a message you sent, then check it and your domain with a multi-list tool such as MXToolbox's blacklist check. A bounce message usually also names the list that blocked you.
My shared hosting server's IP is blacklisted. What should I do?
On Domain India shared hosting, the sending IP is shared by the server and delisting is done by our support team. Open a ticket with the blacklist report or the bounce message, and support will investigate and request removal.
Can I get a different IP for my shared hosting account?
No. Support cannot change the IP address of a shared hosting account. If you need your own IP address, you need a VPS.
Why was my IP or domain blacklisted?
Usually because spam was sent from it: a mailbox with a stolen password, a hacked website script, an abused contact form, or mail to old or bought lists. Fix the cause before requesting delisting, or the listing returns.
Do SPF, DKIM and DMARC prevent blacklisting?
They do not stop a listing if spam is really being sent, but they stop others forging your domain and are now expected by Gmail, Yahoo and Outlook.com. Authenticated mail from a clean source is far less likely to be blocked.
How many emails can I send from Domain India shared hosting?
Outgoing mail is limited to 200 messages per hour per account on Domain India cPanel servers and 1,000 per day on DirectAdmin. Use a newsletter service for bulk mail and include it in your SPF record.
Ready to fix your delivery? Test your mail with How to test email deliverability, check your records with the deliverability deep-dive, or open a support ticket with the blacklist report if our server IP is listed.
Send us the blacklist report or the bounce message, and our support team will investigate and handle the delisting.
Open a support ticket