Dedicated IP or shared?

The effectiveness of your email marketing campaigns could be related to your decision to use either a dedicated or shared Internet Protocol (IP) address.

One of the key challenges of deliverability is achieving and maintaining an excellent sender reputation with ISPs and Webmail service providers. Your sender reputation is one of the deciding factors of whether to block your emails or let them through.

Sender reputation is associated with a sender's IP address – the theory is: if you have a good sender reputation your IP address can be trusted, which equals valid email and a higher delivery potential. There are many additional factors that can affect deliverability, but let's zoom in on the specific issue of dedicated vs. shared IP.

Understanding the implications of a shared IP address

If you are using an ESP to deliver your email marketing campaigns, it's likely that your emails are being sent from a shared IP address used by multiple clients on that system and infrastructure.

Sharing an IP address has many benefits, but there are certain risks too – which a reputable ESP should be managing on your behalf anyway.

The good and the bad of a shared IP address:

• Good sender reputation is developed by consistently sending email, ensuring the bounce rate is kept low and the interaction is high (opens and clicks). If you are not a consistent email sender – sharing an IP enhances your sender reputation by leveraging off other senders on the same IP.
• A good reputation is also derived by adhering to email best practice - benefitting you if these sound policies are adopted by all the senders sharing the IP.
• The flipside of sharing is that you are at risk of other senders behaving badly and should the shared IP earn a poor sender reputation, your deliverability will be adversely affected.
• 
  

If a shared IP is not desirable, then what do you need to know about a dedicated IP?

• You have full control. Your practices alone determine the sender reputation of your IP address. There is no risk of others spoiling the party.
• Unfortunately, the flip side of this is that you need to maintain regular volumes to keep your IP address 'warm', which can be difficult if you do not communicate with your database on a frequent basis (at least weekly – if not daily).
• Over and above this, if you happen to slip up on the odd occasion and not adhere to best practice, you run the risk of putting your IP address under threat of blacklisting. You do not have the luxury of falling back on the good sender reputation achieved by others.

To sum up:

1. You need to discuss the benefits of a dedicated vs. a shared IP address strategy with your ESP.
2. Question their shared IP sender reputation and what proactive measures they are taking to keep their shared environments in good standing with ISP's.
3. Your ESP should also consider your overall communication strategy and advise you on the best fit for your needs, rather than what is best for their needs.

Haydn James
striata.com