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.
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.
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
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.
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
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.
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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