IP Reputation

What is IP Reputation?

IP reputation indicates whether your server's IP address is associated with malicious activity. Poor reputation can result in blacklisting, blocked emails, and restricted services.

Security Impact

Severity: Medium

• Email deliverability issues
• Service blocks
• Domain reputation damage
• Trust issues
• Business disruption

How to Fix

1. Check Current Reputation

# Check multiple blacklists
curl -s https://mxtoolbox.com/api/v1/Lookup/blacklist/YOUR_IP

# Check specific blacklists
host YOUR_IP.zen.spamhaus.org
host YOUR_IP.cbl.abuseat.org

2. If Blacklisted

1. Identify the blacklist
2. Visit their website
3. Request delisting
4. Fix underlying issues
5. Monitor for re-listing

3. Configure Proper rDNS

# Check reverse DNS
dig -x YOUR_IP

# Should match your domain
# Contact hosting provider to set PTR record

4. Implement SPF, DKIM, DMARC

See Email Security documentation.

5. Monitor Email Reputation

• Set up monitoring
• Use email reputation services
• Track bounce rates
• Monitor spam complaints

Prevention

1. Secure your server
2. Prevent spam relay
3. Monitor outgoing emails
4. Implement rate limiting
5. Use authenticated SMTP

Verification Steps

1. Check blacklists regularly
2. Monitor email deliverability
3. Test with mail-tester.com
4. Verify rDNS is configured
5. Check SPF/DKIM/DMARC

Related Issues

• Email Security
• Port Scanning
• Brute Force Protection