If your primary mail server IP address is blocked by spam-checking services (e.g., BARRACUDA, SORBS-SPAM), the best solution is to change the outgoing mail server IP address in Plesk.
On a cPanel server, this is done via /etc/mailips. In Plesk, you need to update the /var/qmail/control/smtproutes file.
Step 1: Check Hosted Domains on the Server
Before modifying the mail server IP, list the domains hosted on the server by running:
cat /var/qmail/control/rcpthosts
🔍 Example Output:
domain1.com
domain2.com
domain3.com
domain4.com
domain5.com
Step 2: Create or Edit the smtproutes File
By default, the smtproutes file does not exist in Plesk. You need to create it manually.
vi /var/qmail/control/smtproutes
Step 3: Assign a New Mail Server IP Address
Add the new outgoing mail server IP in the following format:
domain1.com:192.168.0.2
domain2.com:192.168.0.2
✅ Replace 192.168.0.2 with your actual new IP address.
✅ Replace domain1.com with your actual domain name.
Step 4: Restart Qmail to Apply Changes
After updating the smtproutes file, restart the qmail service:
/etc/init.d/qmail restart
Final Check:
✔ Verify outgoing emails use the new IP by checking the mail logs:
tail -f /var/log/mail.log
✔ Use an email header analysis tool to confirm that outgoing emails are being sent from the new IP.
Benefits of Changing the Mail Server IP:
✅ Avoid blacklisted IPs to improve email deliverability.
✅ Prevent outgoing emails from landing in spam folders.
✅ Enhance email reputation and ensure reliable mail flow.