Warming Up Your IP Addresses Automatically

June 21st, 2018

When sending email messages, there are many best practices for ensuring optimal deliverability.   I.e., for getting your messages into your recipients’ Inboxes and for staying off black lists.  One very important factor in deliverability is “IP reputation.

Good reputation: If your server is known to send lots of good quality email (email that people do not consider spam-like), then your server’s address (its “IP Address”) is looked on favorably by ISPs (such as Yahoo!, Google, Microsoft, etc.) and you can send large quantities of good email and have it all delivered.  Your server has a good reputation and your server’s IP address is “warm” (think warmed up and humming a long).

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 you will have a hard time getting your email delivered and many ISPs will throttle your email, accepting only a few messages a time.  Your server has a poor reputation and work will need to be done to repair it.

No reputation: If you just got a new server, it may not have been sending any email for a while.  Or, if you have a server but it has been idle for a long time (e.g, months).  In either case, your server’s address may have “no reputation.”  ISPs are very skeptical about email from servers with no reputation or recent history 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 they tend to quickly throttle or block such servers…. moving them from “no reputation” towards “bad reputation”.

Warming from No Reputation to Good 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” … it is “cold”.

What is the right way to go from “no reputation” to a “good reputation”?

This process is called “warming up” your IP address.  It involves the following steps:

  1. Start by sending slowly.  Only send a few 10s of email messages per hour in the beginning.
  2. Each day, send more messages.
  3. Over the course or about 1 month, you ramp up to your full sending rate
  4. While sending, especially in the first weeks, send 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 anyway. And 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 to slowly ramp up your sending.  However, we have found that in the majority of cases, sending systems do not know how to properly rate limit email sending.  For these cases, LuxSci has an email throttling feature in your server status and configuration page (go to your 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 your send 24,000 messages.  These will all be queued and then 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, 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 “Automatic IP Warm up” is usually a very good solution as it eliminates all manual work and decision making and takes care of the warm up process for you.  In your server status and configuration page (see screen shot, above), 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 near 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 is having no impact on your IP reputation and the rate limit will not automatically ratchet up
  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 to 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 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 ratchet up to the next level.  This helps make sure that your warm up is actually effective.

DAY Rate: messages/hour Maximum messages/day
1 (Week 1) 20 480
2 30 720
3 40 960
4 55 1320
5 75 1800
6 110 2640
7 150 3600
8 (Week 2) 210 5040
9 300 7200
10 420 10,080
11 580 13,920
12 800 19,200
13 1000 24,000
14 1600 38,400
15 (Week 3) 2250 54,000
16 3100 74,400
17 4500 108,000
18 6000 144,000
19 8500 204,000
20 12,000 288,000
21 17,000 408,000
22 (Week 4) 23,000 552,000
23 33,000 792,000
24 46,000 1,104,000
25 64,000 1,536,000
26 90,000 2,160,000
27 126,000 3,024,000
28 175,000 4,200,000
29 (Week 5) 245,000 5,800,000
30 345,000 8,280,000
31 480,000 11,520,000
32 675,000 16,200,000
33 950,000 22,800,000
34 1,250,000 30,000,000
35 1,800,000 43,200,000


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