Warming Up Your IP Addresses Automatically

September 7th, 2021

When sending email messages, there are many best practices for ensuring optimal deliverability. One very important factor in deliverability is IP reputation. However, when you have a brand new server and IP address, how can you build a good reputation? In this article, we will explain how to warm up an IP address in a way that will help you build a good reputation and improve email deliverability.

warm up ip address

What Is Your IP Reputation?

Good reputation: If your server is known to send lots of good quality email (messages that people do not consider spam-like), then your server’s IP address is looked on favorably by ISPs (such as Yahoo!, Google, Microsoft, etc.). Having a good reputation allows you to send large quantities of good email that will be delivered to recipients. A server with a good reputation has an IP address that we call “warm” (think warmed up and humming along).

Bad reputation: If your server is a known source of junk or malicious email (according to the recipients of the email- it doesn’t matter what you think about the email quality), then many ISPs will throttle your email, accepting only a few messages a time. They may even flag your emails as spam and not deliver them. A server with a poor reputation will need work to repair it.

No reputation: A new server may not have a recent history of sending email. As a result, the IP address may have “no reputation.” ISPs are very skeptical about email from servers with no reputation or without evidence of good email sending. A typical sign of a spammer is when a server with little or no reputation suddenly starts sending large quantities of email. ISPs will detect this and quickly throttle or block such servers…. moving them from “no reputation” towards “bad reputation.”

Warm Up an IP Address from No Reputation

So, you have a new dedicated server and want to start sending a lot of email. The new dedicated server’s IP address is likely to have no reputation, so what can you do to warm it up? More importantly, how do you go from having “no reputation” to a “good reputation”?

To achieve a good reputation, you must “warm up” your IP address. This process involves the following steps:

  1. Start by sending slowly. Send less than 50 email messages per hour in the beginning.
  2. Each day, send more messages.
  3. Over the course of about one month, ramp up to your full sending rate.
  4. Start sending to your best and cleanest email lists. You want all of your email to be liked by your recipients and not marked as spam or flagged as unwanted.
  5. Follow all of the other normal best practices for good email delivery (e.g., good content, good lists, SPF and DKIM records in place, etc.)

By following this warm up process, you can get to your full sending rate in a reasonable amount of time without shooting yourself in the foot by sending too much too soon.

I know that you are anxious to get that first huge email blast off ASAP, but unless you warm up your IP address, those messages won’t land in your recipients’ inboxes. Furthermore, you will have tarnished your server’s reputation such that it will take longer to recover and then properly warm up.

Email throttling and manual IP warm up

If your email sending program has sending rate throttling built into it, you can use that feature to slowly ramp up sending. However, we have found that many sending systems do not know how to properly rate limit email sending. For these cases, LuxSci has an email throttling feature in the server status and configuration page (Existing customers can go to the servers page, click on your server, scroll down to the “Email Queues” section of the Server Vital Signs widget).

When “email throttling” is enabled:

  • You can send to your server as fast as you like.
  • Your server will queue these messages.
  • Your server will send them out based on your specified “email throttling” rate.

For example, if your rate is 1000 messages/hour and you send 24,000 messages, they will be queued and sent out evenly over 24 hours. The first messages received are the first ones sent out.

You can change the throttling rate as desired to manually warm up your IP and/or help you fix problems with tarnished IP reputation.


  1. The actual maximum rate at which your server can send email is a function of many factors, including the power of the server and the nature of the messages sent.  See Sending Rates for more details.
  2. No matter what your configured maximum sending rate is, if you try to send email to more recipients in a month than your overall monthly recipient limit, the excess messages will be rejected.

Automatic IP warm up

For those with new servers, LuxSci’s Automatic IP Warm Up is usually a good alternative as it eliminates all manual work and decision making and takes care of the warm up process for you. Customers can go to the server status and configuration page, enable “Automatic IP Warm Up” and leave “Email Throttling” set to “0” or “-1” (the default, which means “no specific throttling”). Then:

  1. LuxSci enables email throttling and sets the rate limit for today to be very small: 20 messages/hour.
  2. Each night, LuxSci increases the allowed sending rate (see the table below for the schedule) if you have been sending close to your current rate for the entire day.

Your job during the automatic IP warm up process is to:

  1. Actually send messages. If you are not sending email, the warm up will not have an impact on your IP reputation and the rate limit will not automatically increase.
  2. Send enough messages. You want to be sending enough email that your server is mostly sending at close to its maximum allowed rate during the first weeks. In this way, IPs out there see your server progressively sending more and more email. We usually recommend that you send a good size email blast in the beginning and allow that to slowly work its way through the recipients as the IP warms up and the sending rate increases.
  3. Use best practices. As we have said before, it is crucial that the messages you are sending have good content, do not look spammy, and are sent to recipients that actually want your email (i.e., they are unlikely to mark it as spam). Your goal is to prove yourself by sending more and more good email to willing recipients. If you do not follow this advice, then your warm up process may leave you with a bad reputation.

Automatic IP warm up schedule

The following schedule is used for setting your server’s sending rate during the automatic IP warm up period. A day-to-day ramp up progression assumes you are sending as much as the rate limiting allows. If you send less than 90% of your rate-allowed messages during a 24 hours period, your rate will not automatically increase to the next level. This helps make sure that your warm up is actually effective.


DAY Rate: messages/hour Maximum messages/day Total maximum messages sent
1 (Week 1) 20 480 480
2 30 720 1,200
3 40 960 2,160
4 55 1,320 3,480
5 75 1,800 5,280
6 110 2,640 7,920
7 150 3,600 11,520
8 (Week 2) 210 5,040 16,560
9 300 7,200 23,760
10 420 10,080 33,840
11 580 13,920 47,760
12 800 19,200 66,960
13 1,000 24,000 90,960
14 1,600 38,400 129,360
15 (Week 3) 2,250 54,000 183,360
16 3,100 74,400 257,760
17 4,500 108,000 365,760
18 6,000 144,000 509,760
19 8,500 204,000 713,760
20 12,000 288,000 1,001,760
21 17,000 408,000 1,409,760
22 (Week 4) 23,000 552,000 1,961,760
23 33,000 792,000 2,753,760
24 46,000 1,104,000 3,857,760
25 64,000 1,536,000 5,393,760
26 90,000 2,160,000 7,553,760
27 126,000 3,024,000 10,577,760
28 175,000 4,200,000 14,777,760
29 (Week 5) 245,000 5,800,000 20,577,760
30 345,000 8,280,000 28,857,760
31 480,000 11,520,000 40,377,760
32 675,000 16,200,000 56,577,760
33 950,000 22,800,000 79,377,760
34 1,250,000 30,000,000 109,377,760
35 1,800,000 43,200,000 152,577,760


For example, if you wanted to warm up your server so that you could send 30,000 messages in one day, you would need to warm up for 14 days and send to at least 90,960 recipients during that warm up period to progress through those first 14 levels of sending.

If you are interested, but would like more information to help choose your optimal server/cluster capacity and optimize your warm up process, request a Free Consultation.