What is BYOIP?

BYOIP stands for Bring Your Own IP and is a process that allows you to send emails through Twilio SendGrid or other third-party email service providers, using IP addresses that initially existed on your network.

The advantage of BYOIP is that you can use Twilio SendGrid’s scalable email infrastructure while delivering over your already established IP addresses. Regardless of your email provider, BYOIP comes with a number of challenges and requirements. In this article, we’ll breakdown the BYOIP process, and why this may (or may not) be an ideal solution for your email infrastructure. 

The BYOIP process

The BYOIP process is complex (to say the least). It involves updating multiple records and acquiring authorization from a variety of parties to ensure no negative impact on your email delivery and sender reputation. 

We walk through the process in detail to give you a better understanding of what BYOIP involves and the time it takes to accomplish it. However, know that the process outlined below is not Twilio SendGrid-specific, but rather the steps all email service providers should take to successfully implement BYOIP.

1. Letter of Authorization: Before importing any IP addresses, you must establish a Letter of Authorization to identify the IP range moved from your network to Twilio SendGrid. This letter is necessary both for the legal teams of all involved parties, as well as the American Registry for Internet Numbers (ARIN), who manages the distribution of IP resources.

2. Announcement: With the ARIN records updated, you need to “announce” the new ARIN owner via Border Gateway Protocol (BGP) for at least 30 days so that major mailbox providers can randomly ping IPs. These pings verify that the IP addresses exist, confirm connectivity, and identify the network these IPs use.

This step prevents future delivery issues associated with autonomous system numbers (ASN), which are values that uniquely identify separate networks on the internet. Some major mailbox providers (e.g., Microsoft) will not allow IPs to deliver messages that have not had a static ASN assigned for at least 30 days.

3. RADb records: Update Routing Assets Database (RADb) records to change network providers. The RADb is a public registry of routing details for networks that many internet service providers (ISPs) use to verify the true state of an IP’s current network.

4. DNS and rDNS: Before sending, you will need to perform all domain name system (DNS) updates required to deliver email on your end for any sending domains you plan to use. This includes delegating reverse DNS (rDNS) zones for the IP space to Twilio SendGrid DNS servers.

5. Twilio SendGrid: At this point, Twilio SendGrid will make the necessary networking and DNS changes to allow IP porting, including testing the functionality of the ported IPs.

It takes time to thoughtfully and successfully bring your IP addresses to any email service provider, as it requires significant paperwork and consideration of best practices. Pending any unforeseen issues internally or from third parties, the timeline from start to full implementation of BYOIP on any ESP is at least 3 to 4 months. This estimation includes downtime for the IPs and hard cutovers. For fully warmed-up IPs, you can reduce this time to a couple of weeks for the logistics and a few hours for the transfer of IPs to our network.

Considerations for BYOIP

As you can see from the outline above, BYOIP isn’t the “quick fix” for brand-new IPs. While there are certain use cases for BYOIP, you should account for the time consideration.

Length of time

It boils down to the fact that BYOIP is not an alternative to IP warm-up. With a process of 3 to 4 months, BYOIP will likely take longer to implement than an IP to warm up. And once you complete the BYOIP, it is recommended to slowly rewarm these IPs to recipient servers after being in a dormant cooldown state. 

In the same amount of time, you could sign up for a Twilio SendGrid email account and warm up your dedicated IP(s) to a daily email volume of over 500 million.

BYOIP use cases

Migrating from on-premise email infrastructure

BYOIP is not for the average sender and doesn’t provide a shortcut to IP warm-up, but it is useful if you migrate from an on-premise email infrastructure to a cloud-based solution like Twilio SendGrid.

If you migrate from a large range of IPs you own and deliver from, you may already have enough reputation with recipient servers to make it beneficial to port IPs to our infrastructure for continued scaling. You can complete this process in a 2-week time frame for the logistics and the transfer in a few hours.

Sending on behalf of many

BYOIP may be useful if you send on behalf of many customers. If you have a large user base you send on behalf of, you may have many users setting up allow lists with their recipients that include your personal IP ranges. BYOIP would reduce the friction your users see regarding the migration of these allow lists at the cost of potential downtime. (It is worth noting that IP allow lists are mainly for internal or business-to-business sending.)

Whether or not you bring your IPs, moving to Twilio SendGrid would still require a DNS update for anyone wanting to send mail with their domain. Keep this in mind as a necessary step to either migration solution. 

Whichever direction you lean in, we recommend working with our Expert Services and Customer Success teams who have many years of experience making this type of migration successful.


Using BYOIP as an alternative to IP warm-up will land you in hot water.

There will likely be some downtime during which these IPs will not consistently deliver email. During this time, your IP addresses’ reputations will fall out of recipient server algorithms. 

Alternatively, even high volume senders can get ramped up and deliver messages at full scale within 14-30 days using Twilio SendGrid’s dedicated IPs. There are other options to completely avoid downtime. For example, you may have both environments sending mail and slowly migrate mail to Twilio SendGrid from your previous solution to warm Twilio SendGrid dedicated IPs.

Starting fresh is the perfect time to strategically architect for deliverability.

Our Expert Services team has worked with hundreds of enterprise clients to build a unique architecture for each use case that can optimize deliverability on Twilio SendGrid’s IPs. Deliverability is a balance of many variables, and the reputation and history of IPs outside of our normal network is an unknown that you can avoid. Introducing a thoughtful IP warm-up process and architecting the appropriate IP segmentation are key to building a healthy email infrastructure achieved without BYOIP.

Some senders may be right for BYOIP, but it is important to know the pros, cons, and process.

If you are a high-volume sender using an on-premise email infrastructure, BYOIP can help you retain the reputation you have built with recipient servers. If you send on behalf of many customers sending B2B traffic that requires allow lists, BYOIP will remove the need to update allow lists, as migration does not alter IPs. Regardless, you should weigh these pros against the cons, including downtime needed and potential rewarming after IPs cool during the downtime.

Whatever you decide, know that we’re here to help. Discuss the options with our Expert Services team to determine the best direction for your program.

Stevin is a Solutions Architect with experience working in the information technology and services industry helping customers build, design, and manage software solutions to their business problems. Stevin has a Computer Science background and 3 years of experience in the email industry.