Strategic sending: How to choose your IP and domain like a pro

Why a domain and IP strategy matters

When traveling from one place to another, we all understand the opportunities and challenges different vehicles present.

In email marketing, you can think of domain and IP addresses as two pivotal parts of the vehicle that gets your email from point A to point B.

Both are required, and the decisions you make for each have good and bad implications,  depending on your needs and use cases.

This is why it is so important to understand and make intentional decisions about your domain and IP setups in line with your overall email marketing strategy.

In this article, I’ll explore:

• What to watch out for and avoid

• Domain guidance and my recommendation

• IP guidance and my recommendation

• What to do if you’re having trouble with your existing setup 

What to watch out for and avoid

Sometimes taking a good idea too far can lead to more problems than most realize.

Here are some common mistakes I’ve seen that others should avoid in their setup:

• Use of cousin domains
  Cousin domains are also called “lookalike domains” and are domains that look related but aren’t technically connected (business.com vs business.co vs businessemail.com)
  This usage causes a lot of problems, including teaching your customer base that any domain that looks similar to your business’ should be trusted (phishers love this)

• Too many custom IPs, domains, or subdomains
  The amount of traffic required to maintain reputation across multiple IPs or domains can be unsustainable, meaning you  self-sabotage deliverability efforts

• Spammy hosting providers
  Both DNS and Email Providers acquire reputations. Some have come to acquire a poor reputation causing issues for their users. Always do your research to make sure all of your platforms are safe, secure, and have a reputation for reliability

Domain guidance

Every sender’s use case is different but the guiding needs are often similar — here are some options and considerations. 

The main options are:

• Using a shared domain: The shared domain an ESP provides for all customers who would rather use it than their own domain (common but not best practice)

• Using a custom domain: A domain owned and used by your business alone (common and in line with minimum best practice)

• Using a custom subdomain: Same as the “custom domain” only instead of using the root domain (example.com) you would use a subdomain (email.example.com). This is less common but in line with current best practices.

Shared domain pros and cons:

• Pros: 

  • Pre-established reputation

  • Monitored and managed by ESP’s team

  • Helpful for small businesses sending emails in the hundreds each month

• Cons:

  • Shared reputation with other senders using the shared domain (good and bad)

  • Minimum control over deliverability

  • Bad actors can easily spoof your traffic

Custom domain pros and cons:

• Pros: 

  • Reputation separation from other senders

  • Hand’s on control of reputation-based deliverability decisions

  • Ideal for consistent sending of any significant proportion

• Cons:

  • Self-management of reputation

  • Self-management of technical requirements for authentication

  • No good domain reputation shared from other senders

Custom subdomain pros and cons:

• Pros: 

  • Reputation separation from other senders 

  • Reputation separation from traffic on other subdomains within your organization

  • Each subdomain can be managed by its prospective team

• Cons:

  • More subdomains to manage and maintain reputation for

  • More technical setups are required for each subdomain

  • Not 100% separation

My domain advice:

Based on the above, it’s clear that shared domains offer the most advantages for smaller businesses sending <1,000 emails per month. From there, choosing to use either a root organizational domain (example.com) or a subdomain (email.example.com) is more up to the degrees of internal separation needed and the resources/education present for managing the reputation and authentication for whatever option is chosen.

For most bulk senders (Google and Yahoo define that as >5,000 per month), I would suggest a custom subdomain for your marketing efforts and separating sales efforts on their own subdomain if any significant outbound is planned (not ideal but that will protect domain reputation to a degree).

You may ask, “What should our subdomain be?”

My advice is something clear and recognizable for the audience of whatever content stream it will be used for. I’ve seen things like connect.example.com, hello.example.com, and m.example.com to list a few. Dealer’s choice…just keep it simple and recognizable to the audience.

IP guidance

As with domain guidance, every sender’s use case is different but the requirements here are a bit more straightforward  — here are some options and considerations. 

The main options are:

• Using a shared IP pool: This is a shared pool of IPs an ESP provides for their customers who don’t outright need/require a Custom IP (common and in line with best practice)

• Using a custom IP(s): This is a dedicated IP(s) loaned to you by the ESP for your account’s use alone (becoming more common and in line with best practices where advisable)

Shared IP pros and cons:

• Pros: 

  • Pre-established reputation

  • Monitored and managed by ESP’s team

  • Don’t have to worry about tightly managing monthly volumes 

• Cons:

  • Shared reputation with other senders using the shared IPs (good and bad)

  • Minimum control over IP-related deliverability effects

  • Unexpected traffic issues can occur due to traffic patterns, blocklistings, etc.

Custom IP pros and cons:

• Pros: 

  • Reputation separation from other senders

  • Protection from other shared traffic issues

  • Special use cases like IP allowlisting requests for high-security audiences like banks, government agencies, and schools

• Cons:

  • Self-management of reputation and issue remediation

  • Self-management of monthly volumes, which is much stricter than domain volumes

  • No positive IP reputation shared from other senders

My IP advice:

Due to a higher volume threshold required for IP reputation, many bulk and smaller senders can benefit from an ESP’s shared IP pools when properly maintained.

For senders to everyday consumers (freemail addresses), a minimum of 100,000 emails a month is recommended before considering a Custom IP. Any consistent sender of 500,000+ a month can enjoy the benefits of a Custom IP if they are willing to carefully monitor and manage their reputation according to deliverability best practices.

For average senders to organizational addresses (businesses, schools, etc.), the minimum can be lowered to 50,000 emails a month. For those with special use-case requirements (schools sending internally, platforms servicing high-security organizations, etc.) lower volumes are acceptable if either A) custom allowlisting is set up with the receiving mailbox administrators or B) daily max volume is below 5,000 and monthly max volume is below 20,000 (option B is not regularly recommended, especially for growing businesses).

Finally, multiple custom IPs are only advisable if you seek to separate promotional and transactional traffic or need faster delivery to more than 1 million addresses at a time (and the volume-thresholds mentioned above must be reached per IP).

What if I’m having issues with my current setup?

The first step is to take a moment and breathe. Deliverability issues can be fixed. 

As for your current setup, don’t abandon ship just yet. Unless you are on a custom IP and are sending below the advised volume thresholds or are experiencing issues directly related to bad reputation on a shared domain/IP, you should be able to repair any issues you’re currently experiencing. This guide can help you investigate the issue.

Do the work and restore the reputation of your current setup.

Once you have healthy sending practices in place, you can strategize without the pressure of urgency. Use the guidelines I’ve outlined here, along with your current efforts and future plans for growth, to identify the ideal solution.

If you decide on a change, follow your platform deliverability team’s guidance on warming up either a new domain or IP setup. 

If you decide to remain where you are, you can confidently relax knowing you are doing your best work, as far as your domain and IP strategy is concerned.

Final word

Whether you have evaluated your setup due to an issue or not and whether you make changes or not, I just want to say congratulations! You’ve done good work and should be proud.