Summary
When encountering bad reputation foreign IPs associated with your domain in Google Postmaster Tools but no other immediate deliverability issues, a multifaceted approach is recommended. Initially, assess if it's a temporary situation, such as a snowshoe spam campaign that has ceased. Simultaneously, ensure email authentication (SPF, DKIM, DMARC) is correctly implemented and actively monitored through DMARC reports to identify unauthorized sending sources. Investigate for potential subdomain squatting. Thoroughly review email sending practices, checking for compromised accounts by analyzing sign-in logs and mail server logs. Proactively monitor domain reputation, set up alerts for unusual activity, and verify your infrastructure’s integrity. Employ seed list testing and monitor blocklists to detect and address potential deliverability problems before they escalate. List hygiene is also crucial, as is immediate removal of any unauthorized CNAME records to prevent malicious control.
Key findings
- Potential Causes: Bad IPs can indicate a temporary spam campaign, unauthenticated email, compromised accounts, or subdomain squatting.
- Authentication is Key: Ensuring proper SMTP authentication, SPF, DKIM, and DMARC configurations is crucial for preventing unauthorized use.
- Proactive Monitoring: Continuously monitor domain reputation, DMARC reports, mail server logs, and blocklists for unusual activity.
- Immediate CNAME Removal: Remove any unauthorized CNAME records from your subdomains ASAP to prevent malicious parties from using them.
Key considerations
- Balance Monitoring and Action: Decide whether to just monitor the situation or to take immediate action, depending on the effect on legitimate traffic.
- Infrastructure Security: Inspect the email infrastructure for security vulnerabilities and compromised accounts.
- List Hygiene: Follow the principles of good list hygiene to ensure that you are sending email to real people who want your email.
What email marketers say
10 marketer opinions
When encountering bad reputation foreign IPs in Google Postmaster Tools without other apparent deliverability issues, experts recommend a multi-faceted approach. This includes thoroughly reviewing email sending practices, authentication methods (SPF, DKIM, DMARC), and list hygiene. Investigating the root cause of sudden reputation changes is crucial, involving checks for compromised accounts, unusual sending patterns, and infrastructure integrity. Continuous monitoring of domain reputation, setting up alerts for deviations, and using tools to verify authentication configurations are also advised. Checking mail server logs, using seed list testing, and monitoring blocklists are further recommended steps to proactively identify and address potential deliverability problems before they escalate.
Key opinions
- Review Sending Practices: Sender reputation issues should prompt a thorough review of email sending practices, including authentication and list management.
- Investigate Root Cause: Sudden reputation changes necessitate investigating the underlying cause, such as compromised accounts or unusual sending patterns.
- Monitor Authentication: Verifying and continuously monitoring SPF, DKIM, and DMARC records is essential for ensuring proper authentication and preventing spam.
- Proactive Monitoring: Continuous monitoring of domain reputation and setting up alerts are key to identifying and addressing potential issues proactively.
- Subdomain exploitation: Consider subdomain squatting - and stolen subdomains. Run tools like guard.io to check your subdomains are locked down.
Key considerations
- Security: Tighten up security on email accounts and check for unauthorized access as a precautionary measure.
- Mail Server Logs: Checking mail server logs can provide insights into the source of the emails and potential compromise.
- Seed List Testing: Utilizing seed list testing helps monitor deliverability and identify potential issues before they impact sender reputation.
- Blocklist Monitoring: Monitoring blocklists is important for identifying and addressing any listings that could negatively impact deliverability.
- List Hygiene: Maintaining a clean and engaged email list is crucial for sender reputation and deliverability.
Marketer view
Email marketer from Reddit suggests that if you notice bad IPs but no other issues, it might be a good idea to tighten up security on your email accounts and check for any unauthorized access. It’s likely spam, but better safe than sorry.
27 Jan 2025 - Reddit
Marketer view
Email marketer from Mailjet explains that sender reputation issues, even from foreign IPs, should prompt a thorough review of your email sending practices. They advise checking for compromised accounts, ensuring proper authentication (SPF, DKIM, DMARC), and verifying your sending lists are clean and permission-based.
24 Mar 2025 - Mailjet
What the experts say
5 expert opinions
When encountering bad reputation foreign IPs in Google Postmaster Tools without immediate delivery issues, experts offer several courses of action. One perspective suggests it could be a temporary snowshoe spam campaign that has concluded, requiring no further action. Another indicates the issue might stem from unauthenticated email, which would explain the lack of impact. However, experts also strongly advise investigating your email infrastructure for compromised accounts, vulnerable scripts, or open relays. Additionally, immediate removal of any unauthorized CNAME records in subdomains is crucial, as this can grant malicious senders full DNS control. Monitoring DMARC reports and ensuring correct SPF and DKIM implementation are also recommended to prevent future abuse.
Key opinions
- Potential Snowshoe Spam: Bad IPs may indicate a concluded snowshoe spam campaign, potentially requiring no further action.
- Unauthenticated Email: The issue might be due to unauthenticated email, explaining the lack of impact on deliverability.
- CNAME Vulnerability: A compromised CNAME record in a subdomain can grant malicious senders full DNS control, requiring immediate removal.
- DMARC, SPF, DKIM: Monitor DMARC reports to find unauth sending and make sure to lock down SPF/DKIM to prevent further abuse.
Key considerations
- Infrastructure Investigation: Even without immediate delivery problems, investigate your email infrastructure for vulnerabilities and compromised accounts.
- Proactive Security Measures: Implement and maintain robust email authentication and security measures to prevent future abuse.
Expert view
Expert from Email Geeks indicates that the listed foreign IPs likely belong to a single organization engaging in snowshoe spam and suggests that spammers likely used the domain temporarily and are now finished, advising that no further action is needed.
5 Feb 2024 - Email Geeks
Expert view
Expert from Email Geeks recommends immediately removing the CNAME from the affected subdomain, explaining that a CNAME gives malicious senders full DNS control and allows them to send DMARC-passing email.
9 Jun 2021 - Email Geeks
What the documentation says
4 technical articles
When bad reputation foreign IPs are observed in Google Postmaster Tools without other deliverability issues, documentation suggests several actions. Google advises monitoring for a temporary spam campaign and taking no immediate action if legitimate traffic is unaffected. Ensuring proper SMTP authentication is crucial to prevent unauthorized domain use. DMARC.org recommends actively monitoring DMARC reports to identify and address unauthorized sending sources. Microsoft emphasizes reviewing sign-in logs to detect and secure compromised accounts being used for spam.
Key findings
- Temporary Spam Campaign: Bad IPs may indicate a temporary spam campaign, requiring monitoring but potentially no immediate action if legitimate traffic is unaffected.
- SMTP Authentication: Proper SMTP authentication is crucial to prevent unauthorized use of the domain for sending emails.
- DMARC Monitoring: Actively monitoring DMARC reports helps identify and address unauthorized sending sources.
- Account Compromise: Reviewing sign-in logs helps detect and secure compromised accounts being used for spam.
Key considerations
- Monitoring vs. Action: Carefully balance monitoring the situation with taking immediate action, based on the impact on legitimate email traffic.
- Proactive Security Measures: Implementing and regularly reviewing authentication mechanisms is vital for mitigating the impact of malicious actors.
Technical article
Documentation from DMARC.org recommends setting up and actively monitoring DMARC reports to gain insight into who is sending email using your domain, and whether they are properly authorized. This allows you to quickly identify and address unauthorized sending sources, which may include foreign IPs.
2 Jan 2023 - DMARC.org
Technical article
Documentation from RFC Editor states that ensuring that you have proper SMTP authentication to prevent unauthorized use of your domain for sending emails. Implementing and regularly reviewing authentication mechanisms helps to mitigate the impact of malicious actors using your domain's identity.
29 Oct 2022 - RFC 4954
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