Summary
The general consensus is that your origination IP (where you initiate the email send) and your outbound IP (where the email is actually sent from) do not need to be the same, and in many cases, they are not. Experts and documentation emphasize that when using a dedicated Email Service Provider (ESP) like SendGrid, Amazon SES, SparkPost, GMass or Omnisend, the ESP manages the outbound IP reputation. Your application connects to the ESP from an origination IP, but the ESP's infrastructure handles the sending from its own IPs. The SMTP protocol itself supports distinct IPs. However, if you are running your own mail server at home or using PHP's mail() function directly, the origination and outbound IP will likely be the same, a setup discouraged for production environments due to deliverability concerns. Email providers primarily focus on the IP reputation of the outbound IP, and the SPF record should include your outbound IPs. Distinct mail streams from different IPs can also be advantageous.
Key findings
- ESP Separation: When using a reputable ESP, the origination and outbound IPs are typically different.
- Outbound Reputation: Email providers prioritize the reputation of the outbound IP address.
- Dedicated IP Benefits: Using a dedicated IP address through an ESP offers improved control over sending reputation (though you should warm it up properly).
- Self-Hosting Risks: Running your own mail server or using PHP's mail() function with the same origination and outbound IP is risky and not recommended for production.
- SPF Importance: SPF records should include outbound IPs to authorize the sending mail servers.
Key considerations
- Infrastructure Choice: Choose an email infrastructure (ESP or self-managed) that aligns with your technical capabilities and deliverability needs.
- SPF Configuration: Configure SPF records correctly to authorize your outbound IPs and prevent deliverability issues.
- Reputation Management: Actively manage your sending reputation, regardless of whether you're using an ESP or running your own server.
- Deliverability Monitoring: Monitor email deliverability metrics (bounce rates, spam complaints) and adjust your strategy accordingly.
- Mail Stream Segmentation: Consider segmenting your email streams (transactional, marketing) and potentially using different IPs for each to manage reputation and deliverability effectively.
What email marketers say
9 marketer opinions
When sending email, the origination IP (where you initiate the email sending process) and the outbound IP (the IP used to actually send the email) don't necessarily need to be the same, especially when using a dedicated Email Service Provider (ESP). ESPs like SendGrid, SparkPost, GMass, and Omnisend typically manage the outbound IP reputation. If running your own mail server at home or using the PHP mail() function directly, the origination and outbound IP may be the same, but this is not recommended for production due to deliverability issues. Email providers focus on the IP reputation of the outbound IP, not the origination IP. Dedicated IPs are recommended, and warming them up is crucial for sender reputation.
Key opinions
- IP Separation: Using a dedicated ESP generally means your origination and outbound IPs will be different.
- Reputation Focus: Email providers primarily consider the reputation of the outbound IP address for deliverability.
- Dedicated IPs Benefit: Dedicated IPs improve deliverability rates through dedicated warm up of the IP address.
- Home Server Risk: Running your own email server with the same origination and outbound IP is risky for deliverability.
Key considerations
- ESP Choice: Consider using a reputable ESP to manage your outbound IP reputation and ensure better deliverability.
- Infrastructure Setup: Understand your email infrastructure: are you managing your own server, or using a service that handles the outbound IP?
- Deliverability Monitoring: Continuously monitor your email deliverability rates and reputation to identify and address any issues.
- Warm-Up: If you have a dedicated IP address make sure you warm up your IP address to improve your email sending reputation.
Marketer view
Email marketer from SendGrid explains that with dedicated IPs, the outbound IP is typically managed by SendGrid. Your application connects to SendGrid from an origination IP, but SendGrid handles the sending from its own infrastructure using the dedicated IP you've configured.
18 Feb 2024 - SendGrid
Marketer view
Email marketer from Litmus explains that when using a third-party email service, your outbound IP reputation is managed by them. This is separate from your origination IP. They recommend regularly monitoring your deliverability.
25 Dec 2024 - Litmus
What the experts say
4 expert opinions
Experts agree that the origination IP (the IP of the machine initiating the email) and the outbound IP (the IP sending the email to the recipient's mail server) don't have to be the same, and often aren't. This is especially true in cloud-based sending infrastructures where the cloud provider manages the outbound IPs and their reputation. Furthermore, using distinct mail streams from different IPs can be beneficial. If a sender is experiencing rate limiting despite consistent volume, it may indicate a decreased sending reputation.
Key opinions
- IP Distinction: Origination and outbound IPs are often different, particularly with ESPs.
- Cloud Infrastructure: Cloud providers typically handle outbound IPs and their reputation.
- Mail Stream Benefit: Using distinct mail streams from different IPs can be advantageous.
- Reputation Impact: Rate limiting despite constant volume can indicate reputation issues.
Key considerations
- Infrastructure Type: Understand your email infrastructure (in-house vs. ESP) and how it handles outbound IPs.
- Reputation Monitoring: Monitor your sending reputation and address any issues promptly.
- Mail Stream Strategy: Consider separating mail streams for different email types (transactional, marketing) to manage reputation effectively.
- Volume and Rate Limits: If facing rate limits, investigate your sending reputation and potential causes.
Expert view
Expert from Spam Resource explains that in a cloud-based sending infrastructure where multiple IPs are used for sending email, your origination IP would be that of your application server, while the outbound IP would be one of those used by the cloud provider. The cloud provider manages the sending reputation so the outbound IP being the same as the orginating is not required.
1 Feb 2024 - Spam Resource
Expert view
Expert from Email Geeks explains that originating IP and outbound IP don't have to be the same and often aren't. Originating IP is the IP of the machine that initiated the email, while outbound IP is the IP that actually sent the mail to the recipient’s MX.
10 Oct 2023 - Email Geeks
What the documentation says
4 technical articles
Technical documentation indicates that the origination IP (where a client connects to a mail service) and the outbound IP (the IP used to send the email) are often distinct. Services like AWS SES manage outbound IPs. The SMTP protocol inherently separates these IPs. SPF records, which authorize sending mail servers, pertain to the outbound IP, not the origination IP. Conversely, when managing your own email server, the origination and outbound IP are typically the same, requiring careful DNS configuration for proper authentication and deliverability.
Key findings
- SES Management: AWS SES handles outbound IPs, keeping them separate from the origination IP.
- SMTP Protocol: The SMTP protocol intrinsically involves distinct origination and outbound IPs.
- SPF Records: SPF records should include outbound IPs, but not origination IPs when using a third party provider.
- Self-Managed Servers: On self-managed email servers, the origination and outbound IP are usually the same.
Key considerations
- Infrastructure Choice: Your email infrastructure (ESP vs. self-managed server) dictates whether you directly manage outbound IPs.
- SPF Configuration: Properly configure SPF records with the correct outbound IPs to authorize sending mail servers.
- Authentication: When running your own mail server ensure you have proper DKIM and DMARC to improve email deliverability.
- Deliverability Implications: Understanding IP roles is vital for diagnosing and resolving deliverability issues.
Technical article
Documentation from Microsoft explains that SPF records authorize sending mail servers. The outbound IP needs to be included in your SPF record, but your origination IP (where you connect to your ESP) doesn't.
29 Sep 2023 - Microsoft
Technical article
Documentation from Amazon Web Services explains that with Amazon Simple Email Service (SES), you don't manage outbound IPs directly. AWS SES uses a pool of IP addresses to send emails. Your origination IP (where you connect to SES) is separate from the outbound IPs used by SES.
30 May 2023 - Amazon Web Services
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