IP assignment is the process of determining the number of IP addresses required to deliver an email successfully.
As a sender, assigning the appropriate number of IPs is an important part of developing a positive reputation with the mailbox providers. Like warming, IP assignment is determined by a variety of factors; some of these factors include daily/weekly volume, mailing stream (marketing versus transactional/triggered), sender reputation, and ISP distribution.
The following table shows the appropriate number of IPs required to send the different email volumes successfully:
Total Weekly Volume | IPs |
75,000 | 1 |
100,000 | 1 |
200,000 | 1 |
300,000 | 1-2 |
400,000 | 1-2 |
500,000 | 1-2 |
1,000,000 | 2-3 |
2,000,000 | 3-4 |
3,000,000 | 3-4 |
4,000,000 | 5-6 |
5,000,000 | 5-6 |
6,000,000 | 5-6 |
7,000,000 | 6-7 |
8,000,000 | 6-7 |
9,000,000 | 6-7 |
10,000,000 | 7-8 |
15,000,000 | 8-9 |
20,000,000 | 9-10 |
25,000,000 | 10-11 |
30,000,000 | 11-12 |
Note:
- Sending from more IPs than volume dictates can bring a sender’s reputation into question. Spammers employ a process called snowshoeing, where they try to lessen their footprint by sending their volume over a disproportionate number of IPs. As such, it is important to only utilize as many IPs to send your mail as is required.
- Some mailbox providers have very strict limits on the amount of email traffic they allow over a specific period of time. Understanding your email list composition is a key component to understanding how many IPs are necessary to deliver your mail in a timely manner.