Is a 30-day waiting period required when moving to a new IP range using BYOIP?
Matthew Whittaker
Co-founder & CTO, Suped
Published 31 Jul 2025
Updated 16 Aug 2025
6 min read
When moving email infrastructure, especially when bringing your own IP (BYOIP) addresses, a common concern that arises is whether a 30-day waiting period is truly required before you can actively send emails from the new IP range. This question stems from mentions in various documentation, often related to the Border Gateway Protocol (BGP) announcement process. I've encountered this query frequently, and it's a critical point for anyone planning a major migration, as it can significantly impact project timelines and email deliverability strategies.
The idea behind such a waiting period is that major mailbox providers (MBPs) might need time to randomly ping these new IPs. These pings are intended to verify the existence of the IP addresses, confirm connectivity, and identify the network they are currently on. For businesses relying heavily on email, a month-long pause in sending would be incredibly disruptive. Let's delve into whether this 30-day period is a universal requirement or a more nuanced situation, and what it means for your email deliverability.
Cloud provider provisioning timelines
The 30-day waiting period specifically refers to the BGP announcement phase of BYOIP, which ensures global routing tables recognize your IP range under its new ownership and routing. While this networking process is crucial for the IPs to be reachable, it’s often distinct from the internal provisioning times of cloud providers and how email deliverability systems perceive the IPs.
Many cloud providers have their own timelines for the BYOIP process. For instance, AWS documentation notes that the provisioning of BYOIP can take up to three weeks. Similarly, Google Cloud states it takes approximately four weeks for the public advertised prefix to be provisioned. These periods account for the technical and administrative steps involved in verifying ownership with RIRs (Regional Internet Registries) and integrating the IP range into their network, rather than solely a deliverability-focused waiting period.
While the BGP announcement ensures reachability, the reputation of an IP address for email sending is a separate concern. Simply having a routing advertisement stable for 30 days doesn't automatically mean it's ready for high-volume email sending without proper IP warm-up. Mailbox providers evaluate IPs based on sending behavior, spam complaints, bounce rates, and engagement, among other factors.
Mailbox provider considerations for IP routing changes
When you move an IP range, especially one that has been previously warmed up and actively sending mail, the main concern for mailbox providers shifts from initial IP health to the stability of the Autonomous System Number (ASN) where the IP block is now announced. Some MBPs might use ASN stability as a heuristic in their filtering logic, viewing rapidly changing or unstable ASNs as potential indicators of suspicious activity.
This is because bad actors (spammers) sometimes dump routes into the global routing table, send a large volume of spam, and then withdraw the routes, effectively vanishing. To counteract this, some receiving servers might be cautious about traffic originating from IP ranges that have recently undergone significant routing changes or haven't been stable for a certain period. This conservative approach aims to protect their users from malicious activity.
It’s not necessarily about a specific 30-day no-sending window for all providers, but rather a general preference for stability. If an IP address changes its ASN, a period of observation might occur before its full reputation is re-established in the new network context. This is where IP warming strategies become paramount, even for previously warmed IPs.
Understanding the 30-day waiting period
The 30-day claim
Origin: Some sources, including previous documentation from email service providers, have cited a 30-day period for IP announcement via BGP, suggesting it’s for mailbox providers to verify IP existence and connectivity.
Perceived Impact: Implies a lengthy downtime or significantly reduced sending capacity during this period, which can cause significant operational challenges.
Specificity: Often pointed to Microsoft as the requiring entity, though explicit, public confirmation is scarce.
Real-world experience
BGP mechanics: While BGP propagation takes time, it's typically a matter of hours or a few days for routes to become globally visible, not a month for basic reachability.
Deliverability impact: The more significant factor is how mailbox providers evaluate the reputation of an IP when its associated ASN changes. It's about stability for anti-spam heuristics.
Provider variance: Not all email service providers (ESPs) or cloud environments adhere to a strict 30-day waiting period for sending. Some may have internal scheduling times for BYOIP that take weeks, but it's not a technical sending block.
From my experience and discussions within the community, a strict, enforced 30-day waiting period for active sending is not a universal technical requirement for all mailbox providers. While some cloud providers have provisioning periods that can extend to several weeks for BYOIP, this typically involves the administrative and technical steps to bring the IPs into their infrastructure, not necessarily a deliverability-mandated pause in sending traffic.
The 30-day figure might be a very conservative recommendation from some entities to err on the side of caution, especially considering the behavior of spammers using unstable routes. However, the actual impact on your email deliverability will largely depend on your existing IP reputation, the volume of mail, and the specific approach of your new email service provider in managing the BYOIP transition. A hot-swap where large amounts of existing traffic are moved at once can present deliverability challenges, but not necessarily a 30-day block.
Strategies for a smooth BYOIP migration
Minimizing disruption during a BYOIP migration requires careful planning and execution. The goal is to move your sending operations with as little impact to your sender reputation and inbox placement as possible. Even if the IPs are already warmed up, changing the underlying network (ASN) can still trigger reputation reassessments by some ISPs.
Instead of a blanket 30-day waiting period, focus on a gradual transition and monitor your email performance closely. Implement a controlled ramp-up of sending volume on the new infrastructure, even if you are using previously warmed IPs. This allows mailbox providers to observe consistent, positive sending behavior from your IP range within its new network context. This approach aligns with standard IP warm-up best practices, which prioritize consistent, quality sending over rapid volume increases, regardless of IP history.
Engage proactively with your new email service provider to understand their specific BYOIP process and any recommended ramp-up schedules. They often have internal procedures that account for the nuances of IP transitions and can guide you through the process to minimize deliverability impact. This collaboration is crucial for a smooth and successful migration.
Final thoughts on BYOIP migrations
Key takeaways for BYOIP and IP reputation
While a strict 30-day no-sending period for BYOIP isn't a universally enforced technical rule by all mailbox providers, the concept of IP and ASN stability is indeed important. Cloud provider provisioning times for BYOIP can vary, and these should be factored into your migration timeline. The real challenge often lies in how mailbox providers (like Microsoft) react to changes in an IP's network context due to their anti-spam heuristics.
Focus on a gradual ramp-up strategy and maintain clear communication with your email service provider to ensure a successful BYOIP migration. This proactive approach will help you mitigate potential deliverability issues and maintain your sender reputation.
Views from the trenches
Best practices
Maintain strong authentication (SPF, DKIM, DMARC) throughout the transition to signal legitimacy.
Start sending low volumes of highly engaged mail from the new IPs to build a positive sending history.
Monitor email performance metrics, including opens, clicks, and complaint rates, diligently.
Communicate with your cloud provider and ESP about your migration plan for best support.
Common pitfalls
Assuming zero impact if IPs are already warmed up; a network change can still trigger reputation reviews.
Ignoring the difference between BGP propagation time and mailbox provider reputation assessment periods.
Attempting a full 'hot-swap' of high-volume traffic without a phased approach.
Not engaging with your ESP's technical or deliverability teams during the BYOIP process.
Expert tips
If possible, maintain sending from the old infrastructure while gradually ramping up on the new BYOIP range.
Consider engaging with key mailbox providers directly if you anticipate very high volumes.
Ensure your DNS records (e.g., rDNS, SPF, DKIM) are correctly updated for the new IP range.
Be aware that some providers, like Microsoft, are more sensitive to IP and ASN stability than others.
Marketer view
Marketer from Email Geeks says they were initially concerned about a 30-day wait period when moving from Momentum to SparkPost with an existing warmed-up IP range, as it was not mentioned initially by their new provider.
2021-04-12 - Email Geeks
Marketer view
Marketer from Email Geeks says they found the idea of a 30-day pause challenging, as it would prolong their migration process significantly.
Amazon Web Services (AWS)
Google Cloud
Oracle Cloud
Alibaba Cloud
Microsoft as the requiring entity, though explicit, public confirmation is scarce.
Microsoft) react to changes in an IP's network context due to their anti-spam heuristics.
