Summary
The impact of the `x-originating-ip` header on email deliverability is complex and indirect. While some systems analyze the originating IP for spam detection, the `x-originating-ip` header itself might not always be explicitly used or trusted due to the possibility of spoofing. Its presence and weight in spam filtering varies, particularly impacting residential or blacklisted IPs. Key to maintaining deliverability are a clean IP reputation, proper email authentication (SPF, DKIM, DMARC), careful management of IP reputation, and adherence to email sending best practices. Microsoft 365 includes the `x-originating-ip` by default but allows paid subscribers to disable it.
Key findings
- Variable Importance: The direct importance of the `x-originating-ip` header is variable, though the underlying originating IP is often used in filtering.
- Reputation Influence: The reputation of the originating IP has a significant indirect impact on deliverability, whether via `x-originating-ip` or other mechanisms.
- Authentication Crucial: Proper email authentication methods such as SPF, DKIM, and DMARC can improve sender reputation and lessen negative impacts.
- Potential Redundancy: Email systems have other methods to identify sending sources, making the `x-originating-ip` header potentially redundant.
- Configurable on M365: Microsoft 365 enables paid subscribers to remove the `x-originating-ip` header.
Key considerations
- IP Reputation Monitoring: Regularly monitor the IP's reputation and ensure it isn't listed on any blocklists.
- Implement Authentication: Set up robust email authentication protocols (SPF, DKIM, DMARC) to verify sending identity and improve deliverability.
- Careful Sending Practices: Adhere to email sending best practices to maintain a positive sender reputation and avoid triggering spam filters.
- M365 Configuration: If using Microsoft 365, evaluate whether removing the `x-originating-ip` header aligns with your sending strategy and security needs.
- Header Analysis: Analyze email headers to diagnose deliverability issues and adjust sending strategies as needed.
What email marketers say
11 marketer opinions
The `x-originating-ip` header's impact on email deliverability is multifaceted. While not always a direct factor, it can influence deliverability through its contribution to sender and IP reputation. Freemail providers often include it, and it can be removed by Microsoft paying customers. Its significance varies, but it is more pronounced when the IP is associated with residential ranges, known spam sources, or blocklists. Proper email authentication and maintaining a clean IP reputation are crucial for mitigating potential negative impacts.
Key opinions
- `x-originating-ip` Presence: `x-originating-ip` is often included by default, especially with freemail providers like M365, but can be disabled.
- Reputation Impact: A poor IP reputation associated with the `x-originating-ip` can lead to deliverability issues, with some spam filters actively checking it, particularly for residential IPs.
- Indirect Influence: Even if not a direct factor, the `x-originating-ip` contributes to the overall sender reputation, affecting deliverability.
- Authentication: Proper authentication methods (SPF, DKIM) and a positive sender reputation are essential to counteract potential negative impacts.
- Varying Significance: The weight of the `x-originating-ip` header in spam filtering varies depending on the specific filters and the IP's history.
Key considerations
- Monitor IP Reputation: Regularly check the IP associated with your `x-originating-ip` against blocklists and reputation services.
- Implement Authentication: Ensure proper email authentication protocols (SPF, DKIM, DMARC) are correctly configured.
- Maintain Sending Practices: Adhere to best practices for email sending to maintain a positive sender reputation. Avoid sending unsolicited emails to minimize risks.
- Consider Disabling: If using M365, evaluate whether disabling the `x-originating-ip` header is appropriate for your sending practices.
- Review and Adjust: Continuously monitor deliverability rates and adjust sending practices or configurations as needed based on performance.
Marketer view
Email marketer from Litmus shares a blog post about factors influencing email deliverability. While it doesn't directly mention `x-originating-ip`, it discusses how sender reputation, which is partly tied to IP address, significantly affects whether emails reach the inbox or spam folder.
22 Mar 2022 - Litmus
Marketer view
Email marketer from EmailMarketingForum shares that while not always a direct factor, `x-originating-ip` can indirectly impact deliverability through its contribution to overall sending reputation. If the IP is associated with spam or abuse, it can negatively affect deliverability.
25 Jul 2021 - EmailMarketingForum
What the experts say
4 expert opinions
Experts suggest that while `x-originating-ip` might be used in 2nd-received-line filtering, its direct necessity is questionable since filters can analyze headers anyway. Concerns exist regarding trust due to potential spammer manipulation. Crucially, the originating IP's reputation significantly impacts deliverability, making a clean IP reputation vital. Proper authentication (SPF, DKIM, DMARC) is also essential for building a positive sender reputation and reducing spam flags, underlining the relevance of IP information in deliverability.
Key opinions
- Redundancy in Filtering: Filters can analyze headers without relying on the `x-originating-ip`, questioning its necessity for 2nd-received-line filtering.
- Trust Concerns: The `x-originating-ip` header can be faked by spammers, raising doubts about its reliability.
- IP Reputation Importance: Maintaining a clean IP reputation is critical as it directly influences whether emails reach the inbox.
- Authentication's Role: Proper authentication (SPF, DKIM, DMARC) builds a positive sender reputation, mitigating spam flags and highlighting relevance of IP info
Key considerations
- Evaluate Necessity: Assess whether including `x-originating-ip` serves a genuine purpose given potential redundancy.
- Prioritize IP Reputation: Implement practices to maintain and monitor the originating IP's reputation diligently.
- Strengthen Authentication: Ensure robust implementation of SPF, DKIM, and DMARC for better sender authentication.
- Monitor Headers: Continuously analyze email headers to identify and address any deliverability issues.
Expert view
Expert from Word to the Wise discusses the importance of proper authentication (SPF, DKIM, DMARC) for improving email deliverability. Though not explicitly mentioning `x-originating-ip`, it states that authentication helps build a positive sender reputation and reduces the chances of emails being flagged as spam, meaning all information relating to the IP is relevant.
1 Jun 2024 - Word to the Wise
Expert view
Expert from SpamResource explains that maintaining a clean IP reputation is crucial for email deliverability. While they do not directly mention `x-originating-ip`, they emphasize that the originating IP's reputation significantly influences whether emails reach the inbox or are filtered as spam.
26 Jan 2025 - SpamResource
What the documentation says
5 technical articles
Documentation from various sources highlights the importance of the originating IP address in email deliverability. While not always explicitly mentioning `x-originating-ip`, these resources indicate that the originating IP is analyzed for spam detection, tracked for reputation, and is a key factor for ISPs identifying legitimate senders. Maintaining a good IP reputation, using properly configured headers, and employing IP warming strategies are critical for ensuring deliverability.
Key findings
- Originating IP Analysis: Email systems analyze the originating IP address as part of their spam detection and filtering mechanisms.
- Reputation Tracking: The originating IP is tracked for its sending behavior and reputation, influencing deliverability decisions.
- Header Importance: Properly configured email headers are essential for helping ISPs identify legitimate senders.
- Deliverability Tie: Deliverability is closely tied to the originating IP address, including its history and reputation.
Key considerations
- Monitor IP Reputation: Continuously monitor and manage your IP reputation to avoid being blacklisted.
- Proper Header Configuration: Ensure all email headers are properly configured according to industry standards.
- IP Warming: Implement a gradual IP warming strategy when introducing new IP addresses for sending emails.
- Authentication Protocols: Utilize authentication protocols such as SPF, DKIM, and DMARC to verify your sending identity.
Technical article
Documentation from SparkPost covers common email deliverability issues. They discuss IP warming and maintaining a good IP reputation. Although not explicitly mentioning `x-originating-ip`, it highlights how closely deliverability is tied to the originating IP address and its history.
6 Jun 2024 - SparkPost
Technical article
Documentation from Microsoft Learn explains that Exchange Online Protection (EOP) and Office 365 Advanced Threat Protection (ATP) use various methods to identify and block spam, including analyzing the originating IP address of the sending server. While not explicitly mentioning `x-originating-ip`, it implies that the originating IP is a factor in deliverability.
1 Aug 2024 - Microsoft Learn
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