Summary
The deliverability of emails sent from a dedicated IP heavily relies on maintaining consistent and predictable sending volumes. Sudden and significant peaks in email volume, especially after periods of low activity, or abrupt dips followed by attempts to resume normal sending, are major risks. Internet Service Providers (ISPs) view such erratic patterns as suspicious, potentially signaling spamming, the use of purchased lists, or even a compromised account. This inconsistency erodes the sender's hard-earned IP reputation, leading to harsh rate limiting, emails being diverted to junk folders, throttling, or outright blocking. ISPs prefer a steady sending curve, as it allows them to accurately assess sender behavior and maintain trust, making gradual volume changes crucial for sustained inbox placement.
Key findings
- Erratic Volume Harms Reputation: Inconsistent sending patterns, including sudden peaks or significant dips in volume on a dedicated IP, appear suspicious to Internet Service Providers (ISPs) and severely damage the IP's hard-earned reputation.
- ISP Rate Limiting and Filtering: Sudden, large increases in sending volume can trigger harsh rate limiting and stricter filtering by ISPs, leading to important emails being rejected, deferred, or redirected to spam or junk folders.
- Dips Require Re-warming: Significant drops in sending volume can cause ISPs to treat the sender as 'AWOL,' necessitating a re-warming process and lower restart volumes to regain their trust and avoid deliverability issues.
- Consistency is Key: ISPs prioritize consistent and predictable sending patterns for dedicated IPs because this builds and maintains trust, which is crucial for achieving high inbox placement and reliable email delivery.
Key considerations
- Avoid Sudden Spikes: Refrain from dispatching excessively high volumes of email too rapidly, particularly following periods of inactivity, as this can trigger spam filters and significantly damage your dedicated IP's reputation.
- Maintain Regular Cadence: Strive for a steady and consistent sending volume to build and preserve a strong, trustworthy IP reputation with Internet Service Providers (ISPs) and mailbox providers.
- Gradual Volume Adjustments: Introduce any changes to your sending volume gradually, akin to an IP warming process, allowing ISPs to detect and adapt to the new pattern without flagging it as suspicious.
- Understand ISP Expectations: Recognize that ISPs expect predictable and consistent behavior from dedicated IPs; any significant deviation from established patterns can lead to increased scrutiny and severe deliverability problems.
What email marketers say
14 marketer opinions
Dedicated IPs are highly sensitive to sending volume fluctuations. Sudden, sharp increases in email volume, such as a 7.5x jump, can immediately trigger ISP detection systems, leading to severe rate limiting, blocks, or emails being diverted to spam. Similarly, significant dips in sending volume, especially if followed by an attempt to quickly resume high volume, signal inactivity to ISPs. This can cause the IP to be perceived as 'cold' or 'AWOL,' damaging its reputation and requiring a re-warming period. Internet Service Providers prioritize a smooth, predictable sending curve because it allows them to accurately assess sender behavior and maintain trust. Any erratic patterns, whether peaks or dips, are seen as red flags, indicating potential spamming or unusual activity, which ultimately impairs deliverability.
Key opinions
- Sudden Peaks Trigger Limits: Rapid, significant increases in email volume, even within hours, can lead to harsh rate limiting and immediate throttling by Internet Service Providers, preventing critical emails from reaching their intended inboxes.
- Inconsistent Volume Erodes Trust: Erratic sending patterns, whether sudden peaks or prolonged dips, appear suspicious to ISPs. This inconsistency damages the dedicated IP's hard-earned reputation, potentially signaling a compromised account or purchased lists.
- Dips Require Reputation Rebuild: Significant drops in sending volume followed by an attempt to resume normal levels can cause deliverability issues. ISPs may perceive such an IP as 'AWOL,' requiring a gradual re-establishment of trust at lower volumes.
- Predictability Boosts Deliverability: Consistent and predictable sending patterns are crucial for building and maintaining a strong IP reputation. ISPs rely on this stability to assess sender behavior accurately, leading to better inbox placement.
Key considerations
- Implement Gradual Scaling: When increasing sending volume, aim for gradual ramps, such as a 3x or 4x increase over several months, rather than sudden, overnight spikes, to allow Internet Service Providers to adapt without flagging your activity as suspicious.
- Maintain Predictable Patterns: Prioritize a consistent sending cadence and volume, as ISPs learn and expect specific patterns from dedicated IPs. Any significant deviation can prompt them to re-evaluate your sender score.
- Re-warm After Inactivity: If there has been a significant dip or extended period of inactivity, recognize that ISPs may treat your IP as 'AWOL.' Re-establish your sending reputation with a lower, re-warming volume before attempting to resume normal activity.
- Introduce Changes Gradually: Any alterations to your sending identifiers, behaviors, or content should be introduced incrementally. This helps mailbox providers detect and adjust to your new pattern, supporting sustained deliverability.
Marketer view
Marketer from Email Geeks shares a personal experience where a rapid 7.5x volume increase on one IP led to the IP being listed, causing issues. They suggest that a 3x or 4x increase over several months is more reasonable, akin to a warming ramp, but still advises caution regarding sudden spikes and sustained volume.
14 Dec 2021 - Email Geeks
Marketer view
Marketer from Email Geeks explains that sudden, significant volume peaks (e.g., 2.5-3.5x increase in hours) can lead to harsh rate limiting by ISPs, preventing important emails from reaching the inbox. They also explain that significant dips in sending volume, followed by an attempt to resume normal volume, can result in deliverability issues because ISPs will treat the sender as "AWOL," requiring a lower restart volume.
21 May 2022 - Email Geeks
What the experts say
3 expert opinions
On a dedicated IP, email deliverability is acutely vulnerable to erratic sending behaviors. Both rapid, excessive surges in volume and significant lulls followed by a sudden burst can be detrimental. Internet Service Providers (ISPs) interpret such inconsistent patterns as suspicious activity, potentially indicating spamming, the use of purchased lists, or a security compromise. This inconsistency erodes the IP's hard-earned sender reputation, leading to increased spam filtering, message rejections, or outright blocking. Maintaining a steady, predictable sending volume is paramount, as ISPs favor a consistent cadence to accurately assess sender trustworthiness and ensure reliable inbox placement.
Key opinions
- Sudden Spikes Trigger Filtering: Large, abrupt increases in email volume on a dedicated IP can immediately flag your activity as suspicious, leading to increased spam filtering or outright blocking by Internet Service Providers.
- Inactivity Requires Re-warming: Prolonged periods of low email volume or complete inactivity, especially when followed by a sudden high-volume burst, can harm your dedicated IP's reputation, necessitating a re-warming process to regain ISP trust.
- Consistency Builds Trust: Maintaining a consistent and steady email sending pattern is crucial for building and preserving a positive IP reputation with ISPs, which directly translates to better inbox deliverability.
- ISPs Prefer Predictability: Internet Service Providers favor predictable and gradual sending behavior over sudden, erratic volume changes, often imposing implicit volume limits and penalizing rapid, unmanaged increases.
Key considerations
- Avoid Abrupt Volume Changes: Refrain from significant, rapid shifts in your email sending volume, particularly after periods of low activity, to prevent triggering ISP spam filters and damaging your dedicated IP's standing.
- Prioritize Steady Sending: Aim for a regular, consistent email cadence and volume to establish and maintain a robust sender reputation with mailbox providers, ensuring more reliable inbox delivery.
- Re-engage Gently After Dips: If your sending volume has significantly dipped or paused, resume activity gradually, effectively re-warming your dedicated IP to rebuild trust with ISPs before attempting higher volumes.
- Understand ISP Volume Thresholds: Be aware that ISPs have internal volume limits and prefer a gradual, consistent approach to email sending; rapid scaling can lead to message rejection or misdirection to spam folders.
Expert view
Expert from Spam Resource explains that large, sudden spikes in email volume or prolonged periods of inactivity followed by a sudden burst can negatively impact an IP's reputation, leading to increased spam filtering or blocking by ISPs. Consistent and steady sending is crucial for maintaining a good IP reputation and deliverability.
1 Oct 2021 - Spam Resource
Expert view
Expert from Word to the Wise explains that taking long breaks from sending email, or experiencing significant dips in volume, can harm deliverability on a dedicated IP. ISPs prefer consistent sending patterns, and resuming high volume after a lull can appear suspicious, leading to a need to re-warm the IP and potential increased filtering or blocks.
6 Jan 2024 - Word to the Wise
What the documentation says
4 technical articles
Major email service providers and industry leaders consistently highlight that the reputation of a dedicated IP is highly susceptible to inconsistent sending volumes. Both sharp, unmanaged increases and significant, prolonged decreases in email volume pose substantial deliverability risks. ISPs, including Google, Microsoft, SendGrid, and AWS SES, interpret these erratic patterns as red flags, which can suggest suspicious activity, such as spamming or unauthorized usage. This leads to a degradation of the IP's hard-earned sender reputation, resulting in emails being filtered to junk folders, throttled, or outright rejected, underscoring the critical need for a stable and predictable sending cadence.
Key findings
- Reputation Impact: Erratic sending volumes, whether sudden spikes or prolonged dips, are consistently flagged by ISPs as suspicious, directly harming a dedicated IP's sender reputation.
- Filtering and Rejection: Mailbox providers like Google, Microsoft, and others respond to volume inconsistencies by applying stricter filtering, leading to emails being junked, deferred, or blocked.
- Re-warming Necessity: Periods of significant inactivity or low volume on a dedicated IP necessitate a careful re-warming process to rebuild trust and ensure future deliverability when volumes increase again.
- Provider Consensus: Leading email platforms and tools, including SendGrid, Google Postmaster Tools, Outlook Postmaster, and AWS SES, all emphasize consistent sending as fundamental for dedicated IP deliverability.
Key considerations
- Avoid Extreme Fluctuations: Steer clear of abrupt and drastic changes in email sending volume to prevent triggering ISP suspicion and damaging your IP's reputation.
- Prioritize Consistent Cadence: Establish and maintain a steady and predictable sending schedule to foster a reliable and positive sender reputation with mailbox providers.
- Gradual Volume Adjustments: Implement any increases or decreases in email volume incrementally, allowing ISPs to adapt to your sending patterns without perceiving them as anomalies.
- Address Inactivity Strategically: If your dedicated IP experiences a significant dip in volume, plan a gradual re-entry strategy, similar to initial IP warming, to restore trust before scaling up.
Technical article
Documentation from SendGrid explains that maintaining a consistent sending volume is crucial for dedicated IP reputation, especially after the initial IP warming phase. Sudden peaks or prolonged dips in sending volume can negatively impact the sender's reputation, causing delivery issues as ISPs may flag such erratic patterns as suspicious.
9 Jul 2023 - SendGrid Documentation
Technical article
Documentation from Google Postmaster Tools explains that maintaining a consistent sending pattern and building a good sending reputation are crucial for email delivery to Gmail users. Sudden increases in sending volume or inconsistent sending patterns on a dedicated IP can trigger stricter filtering by Gmail and significantly lower the IP's reputation, impacting deliverability.
15 May 2023 - Google Postmaster Tools Help
Does decreased weekend volume on a dedicated IP affect deliverability?
How do email volume and volume fluctuations affect deliverability and sender reputation?
How do I address deliverability issues for very low volume transactional emails on a dedicated IP?
How does erratic sending impact deliverability on dedicated IPs, especially for consumer domains in the US?
When should I use dedicated IPs vs shared IPs for inconsistent, high-volume email sends?
When to consider multiple dedicated IPs for large email lists and what causes deliverability degradation?
