Summary
To mitigate throttling when sending emails to wanadoo.fr and orange.fr, a combination of strategies is recommended. Limiting the number of concurrent connections to a single mail server, as suggested by RFC 5321, is crucial. Specific recommendations include using 1-3 connections max per IP address, sending messages at a rate of 50-100 per minute per connection, and setting an overall limit on the number of messages sent per hour. Proper SPF, DKIM, and DMARC configuration, maintaining a good sender reputation, monitoring bounce rates, implementing retry mechanisms, and gradually increasing sending volume are also important factors. Throttling policies are frequently based on observed sending behavior, so ramping up slowly and monitoring delivery are essential, and individual MX records endpoints might require unique handling.
Key findings
- Connection Limits: Limiting connections to 1-3 per IP address is a common strategy.
- Message Rates: Capping message rates to 50-100 messages per minute per connection helps.
- Hourly Limits: Implement overall hourly limits to prevent bursts that trigger throttling.
- Authentication: Proper SPF, DKIM, and DMARC setup are essential for deliverability and trust.
- Behavioral Throttling: ISPs often base throttling on observed sending patterns rather than fixed limits.
- Individual MX Treatment: If different MX records are used, each might need specific configuration.
Key considerations
- Sender Reputation: Maintaining a good sender reputation is crucial for deliverability.
- Bounce Monitoring: Actively monitor and address bounce rates to improve sending health.
- Gradual Ramp-Up: Slowly increase sending volume to avoid being flagged as a spammer.
- Delivery Monitoring: Closely monitor email delivery rates to identify potential issues.
- Connection Management: Adhere to SMTP standards by limiting concurrent connections.
- Endpoint Configuration: Handle different MX records differently, adjusting to their specific rate limits.
What email marketers say
5 marketer opinions
To avoid throttling when sending emails to wanadoo.fr and orange.fr, email marketers recommend limiting connection and message rates. Specific recommendations include using 1 connection max for each domain, limiting messages to 50-100 per minute per connection, and setting an overall limit of around 90,000 messages per hour. Maintaining a good sender reputation, proper authentication (SPF, DKIM, DMARC), monitoring bounce rates, and implementing retry mechanisms are also crucial.
Key opinions
- Connection Limits: Limiting connections to 1-3 per IP address is a common recommendation.
- Message Rates: Capping message rates to 50-100 messages per minute per connection helps prevent throttling.
- Overall Limits: Setting hourly limits (e.g., 90,000 messages per hour) can further reduce throttling issues.
- Authentication: Proper SPF, DKIM, and DMARC configuration is essential for deliverability.
Key considerations
- Sender Reputation: Maintaining a good sender reputation is critical for avoiding throttling.
- Bounce Monitoring: Monitoring and addressing bounce rates helps improve deliverability.
- Retry Mechanisms: Implementing retry mechanisms for failed connections can improve sending success.
- Ramping Up: Slowly increasing sending volume allows senders to assess the limits of a domain.
Marketer view
Email marketer from Email Marketing Forum mentions a successful strategy of using 1 connection and limiting to 50 messages per minute per connection when sending to Wanadoo. They also emphasize the importance of maintaining a good sender reputation.
28 Oct 2024 - Email Marketing Forum
Marketer view
Email marketer from Email Geeks details client-specific rate limits: Client 1 has 1 connection max, 100 messages per connection max, and 90,000 messages max every 3600 seconds. Client 2 is similar, with a max of 2 connections and 100 messages per connection max. This configuration significantly reduced throttling from wanadoo, orange, voila, and francetelecom.
29 Jun 2024 - Email Geeks
What the experts say
2 expert opinions
Experts emphasize that throttling policies for wanadoo.fr and orange.fr are typically based on observed sending behavior. Specific rate limits are often unpublished, making it crucial to ramp up sending slowly while closely monitoring delivery. If different MX records are used, each endpoint may require individual treatment and configuration.
Key opinions
- Behavior-Based Throttling: Throttling is often determined by observed sending behavior from an IP address or domain.
- Unpublished Rates: Specific connection and message rate limits are generally not publicly available.
- MX Record Differentiation: If multiple MX records are in use, treat each endpoint independently.
Key considerations
- Gradual Ramp-Up: Increase sending volume slowly to avoid triggering throttling mechanisms.
- Delivery Monitoring: Closely monitor email delivery rates to identify and address potential throttling issues.
- Endpoint Specific Configuration: If you have multiple MX records ensure each is configured correctly and throttled in line with the endpoint requirements.
Expert view
Expert from Spam Resource, John Levine, explains that throttling policies are frequently based on observed sending behavior from a specific IP address or sending domain. The specific rates aren't published, and it's best practice to ramp up slowly and monitor delivery.
30 Jul 2024 - Spam Resource
Expert view
Expert from Word to the Wise, Laura Atkins, answers that if you have different MX records, it might be necessary to treat each MX endpoint a bit differently.
4 Apr 2022 - Word to the Wise
What the documentation says
3 technical articles
Email deliverability documentation emphasizes limiting concurrent connections to a single mail server to prevent overloading. RFC 5321 recommends exponential backoff for connection failures. Throttling depends on the domain, so a general guideline is to send as slowly as possible while maintaining necessary speed; excessive connections can lead to dropped connections. PowerMTA utilizes a single configuration value for managing limits, adjustable at the domain or source level, with some ISPs requiring low connection limits (1-2).
Key findings
- Limit Concurrent Connections: SMTP clients should limit the number of concurrent connections to avoid overloading servers.
- Exponential Backoff: Implement exponential backoff for failed connection attempts as per RFC 5321.
- Domain-Specific Throttling: Throttling is domain-dependent; send as slowly as possible while meeting needs.
- Low Connection Limits: Some ISPs may require very low connection limits (e.g., 1-2).
Key considerations
- Avoid Server Overload: Ensure sending practices do not overload receiving mail servers.
- Adapt Sending Speed: Adjust sending speed based on domain requirements; avoid unnecessary speed.
- Configure Limits: Utilize configuration options (e.g., PowerMTA) to enforce connection limits.
- ISP Requirements: Adhere to specific connection limit requirements of individual ISPs.
Technical article
Documentation from PowerMTA documentation mentions they use a single config value to handle limits. This can be configured in the domain or the source level. Some ISPs require low connection limits of 1 or 2.
29 Jul 2021 - PowerMTA
Technical article
Documentation from IETF explains that the RFC 5321 (Simple Mail Transfer Protocol) recommends that SMTP clients limit the number of concurrent connections to a single mail server to avoid overloading the server. It suggests implementing exponential backoff for failed connection attempts.
25 Jul 2021 - IETF
How do I find a postmaster contact at Terra.com.br and handle throttling issues?
How do PowerMTA's retry-after, max-connect-rate, max-smtp-out, max-msg-per-connection, and max-msg-rate directives work?
How to troubleshoot Orange.fr bounces (SMTP greeting failed) in Klaviyo?
What are common connection and message limits imposed by different email providers?
What causes unclassified soft bounces from Orange.fr in Klaviyo, and how can they be resolved?
Why is email delivery to Orange and Wanadoo slow?
