Summary
Effectively managing email throttling from new IPs and recipient domains requires a holistic approach encompassing technical setup, sender reputation management, content optimization, and continuous monitoring. Key strategies include implementing a gradual IP warm-up process, respecting recipient domain connection limits (especially those like orange.fr and wanadoo.fr), optimizing messages per connection, using the MTA's built-in throttling, and actively monitoring sender reputation. Encouraging subscriber engagement, segmenting email lists, using authentication protocols (SPF, DKIM, DMARC), avoiding spam triggers, regularly cleaning email lists, and understanding SMTP error codes are also crucial. Additionally, a robust bounce management system, handling greylisting, participating in feedback loops, and adhering to SMTP rate limits contribute significantly to avoiding throttling and ensuring deliverability.
Key findings
- IP Warm-up: Gradually increasing email volume from new IPs is crucial; reduce volume if encountering 'too many messages' errors.
- Connection Limits: Adhere to recipient domain connection limits; orange.fr and wanadoo.fr combined allow only 3 simultaneous connections.
- Messages per Connection: Senders prefer fewer connections with more messages; 500 messages per connection is a good balance.
- Sending Volume: Aim for 100,000 messages per hour per IP; 1 million per day is a normal expectation.
- MX vs Domain: Connection limits are often per MX record, not per domain.
- MTA Throttling: Leverage the MTA's built-in throttling for up-to-date rules.
- Sender Reputation: Monitor sender reputation metrics (bounce rates, complaints); implement feedback loops.
- Engagement: Encourage subscriber engagement through personalized content.
- Segmentation: Segment lists based on engagement to target active subscribers.
- Spam Triggers: Avoid spam triggers in content/subject lines.
- List Cleaning: Regularly clean email lists.
- Email Authentication: Implement SPF, DKIM, and DMARC.
- Rate Limits: Adhere to SMTP rate limits.
- Bounce Management: Implement a robust bounce management system.
- Greylisting: Configure servers to retry emails deferred due to greylisting.
- SMTP Error Codes: Check error codes.
- Ramp up slowly: Increase Volume slowly and steadily.
- Monitoring: Monitor Sender Reputation via tools.
Key considerations
- Pace Yourself: Warm-up your IPs slowly. Don't try to rush the process.
- Plan the connections: Think about connections to MX records not just domains.
- Get the right MTA: Make sure the MTA you choose has up-to-date features.
- Hygiene is key: Implement regular cleanup tasks to maintain deliverability.
- Act fast: Make sure the data is analyzed pro-actively
What email marketers say
13 marketer opinions
Successfully handling throttling from new IPs and recipient domains involves a multi-faceted approach encompassing technical configurations, reputation management, and content optimization. Key strategies include gradually warming up new IPs, adhering to connection limits imposed by recipient domains, monitoring sender reputation metrics, engaging subscribers with personalized and valuable content, and maintaining clean email lists. Furthermore, avoiding spam triggers, segmenting lists, using email authentication protocols, and actively managing bounce and complaint rates are essential for preventing throttling and ensuring optimal email deliverability.
Key opinions
- IP Warm-up: Gradually increasing the volume of email sent from new IPs is essential for building a positive reputation.
- Connection Limits: Recipient domains enforce connection limits; adhering to these limits prevents throttling. Orange.fr and Wanadoo.fr, when combined, only allow a maximum of 3 connections.
- Messages Per Connection: Receivers prefer fewer connections with more messages per connection, with 500 messages being a suggested balance.
- Sending Volume: A realistic hourly sending target is 100,000 messages per IP for most senders.
- Sender Reputation Monitoring: Monitoring sender reputation metrics (bounce rates, complaints) is critical to address deliverability issues proactively.
- Subscriber Engagement: Encouraging subscriber engagement through personalized content improves sender reputation and reduces throttling.
- List Segmentation: Segmenting email lists based on engagement allows targeted emails to active subscribers, improving deliverability.
- Content Relevance: Delivering valuable and relevant content boosts engagement and signals positive intent to recipient domains.
- Spam Triggers: Avoiding spam triggers in content and subject lines prevents emails from being flagged and throttled.
- List Hygiene: Regularly cleaning email lists to remove inactive addresses enhances deliverability.
- Ramp up Slowly: Increasing sending volume needs to be gradual. Doubling volume weekly is suggested, not daily or even rapidly.
- Reputation Monitoring: Monitor Sender Reputation via Google Postmaster Tools to asses the status of deliverability and any issues needing adressed.
Key considerations
- Balance: Finding the right balance between sending volume and connection limits is crucial for optimal deliverability.
- Proactive Monitoring: Implementing continuous monitoring of sender reputation and engagement metrics enables timely issue identification and resolution.
- Content Quality: Prioritizing content quality and relevance is essential for maintaining subscriber engagement and positive reputation.
- Cleanliness: Maintaining clean and engaged email lists helps minimize bounce rates and improves overall deliverability.
- Throttling is domain specific: Different domains have different ways of throttling traffic, so it's essential to treat them all differently
Marketer view
Marketer from Email Geeks advises that 100,000 messages per hour per IP is a more realistic target than 1,000,000 which is only achievable by the highest reputation senders.
11 Mar 2022 - Email Geeks
Marketer view
Email marketer from Mailjet shares that it is important to monitor sender reputation metrics, such as bounce rates and spam complaints, to identify and address any issues that could lead to throttling. Implementing feedback loops and promptly removing unsubscribed recipients can help maintain a positive reputation.
25 Aug 2023 - Mailjet
What the experts say
8 expert opinions
Effectively managing email throttling from new IPs and recipient domains involves a combination of technical understanding, adaptive strategies, and proactive monitoring. Key best practices include properly warming up new IPs at a sustainable pace, understanding that connection limits are generally per MX record, leveraging MTA's built-in throttling rules, and closely monitoring SMTP error codes to identify throttling issues. Additionally, implementing robust bounce management, addressing greylisting, and participating in feedback loops (FBLs) are crucial for maintaining a clean sending reputation and preventing throttling.
Key opinions
- IP Warm-up Pace: If experiencing 'too many messages from new IP' errors, the warm-up process is likely too fast; reduce sending volume.
- Connection Limiting: Connection limiting is usually based on the number of connections to an MX record, not per receiving domain.
- MTA Throttling: Using the built-in throttling mechanisms of your MTA is generally more effective than manual throttling.
- Daily Volume Expectation: A normal expectation is 1 million emails per IP per day.
- SMTP Error Codes: Understanding SMTP error codes (4xx) is essential for diagnosing throttling issues.
- Bounce Management: Implementing robust bounce management is crucial for maintaining a clean sending reputation.
- Greylisting: Greylisting can appear as throttling; configure servers to retry deferred emails.
- Feedback Loops: Participating in FBLs allows identification and removal of abusive recipients, improving sender reputation.
Key considerations
- Warm-up is critical: Prioritize a slow and steady warm-up process to avoid triggering throttling mechanisms.
- Mx record vs domain: Understanding the difference between MX record and domain-based throttling is important for proper configuration.
- Automate where possible: Leverage the features of your MTA to automate throttling processes.
- Proactive Monitoring: Monitor SMTP error codes and actively manage bounces and spam complaints to maintain a positive sending reputation.
- Use data: Use the data from SMTP error codes and feedback loops to make decisions about sending volumes, and user un-subscriptions.
Expert view
Expert from Email Geeks recommends backing off to the level where sending was successful for 2-3 days and states that if getting ‘too many messages from new IP’ it means the warmup is too fast.
16 Apr 2023 - Email Geeks
Expert view
Expert from Email Geeks explains connection limiting is usually based on how many times a particular IP has opened any connection to their MX machines, so it’s per MX not per receiving domain.
24 Oct 2021 - Email Geeks
What the documentation says
5 technical articles
Managing email throttling effectively involves several technical and procedural best practices. Gradually warming up new IPs, limiting concurrent connections using connection pooling, implementing email authentication (SPF, DKIM, DMARC), adhering to SMTP rate limits, and actively monitoring sending activity (bounce rates, complaints) are crucial steps to establish a positive sending reputation and prevent throttling by recipient domains.
Key findings
- IP Warm-up: Gradually increase email volume from new IPs over weeks to build a positive reputation.
- Connection Pooling: Limit concurrent connections and reuse existing connections to avoid overwhelming recipient domains.
- Email Authentication: Implement SPF, DKIM, and DMARC to verify sender identity and prevent spoofing, boosting deliverability.
- SMTP Rate Limits: Understand and adhere to SMTP rate limits to avoid overwhelming recipient servers.
- Activity Monitoring: Monitor sending activity, including bounce rates and complaints, using ESP dashboards and reports.
Key considerations
- Gradual Approach: Prioritize a gradual and controlled increase in sending volume during IP warm-up.
- Technical Implementation: Correctly implement connection pooling and email authentication protocols.
- Compliance: Adhere to SMTP rate limits specified by recipient domains.
- Proactive analysis: Establish proactive monitoring of sending activity to quickly address any issues.
Technical article
Documentation from Microsoft answers implementing email authentication protocols such as SPF, DKIM, and DMARC can help verify the sender's identity and prevent email spoofing, which can lead to throttling. These protocols provide assurance to recipient domains that the email is legitimate and not spam.
14 Aug 2024 - Microsoft
Technical article
Documentation from SparkPost responds that limiting the number of concurrent connections to recipient domains can help prevent throttling. They suggest implementing connection pooling and reusing connections to reduce the overhead of establishing new connections for each email.
6 Jun 2024 - SparkPost
Do I need an IP warm-up when moving to a new ESP with shared IPs?
How can staggering email sends improve sender reputation and avoid throttling?
How do I contact the Yahoo postmaster for deliverability issues during IP warm-up?
How do I resolve temporary deferral errors and warm up new IP addresses for transactional emails on Yahoo?
How do I warm up a new IP address for transactional emails?
How do I warm up new IP addresses for email sending?
