Dedicated vs Shared IP
Email MarketingAlso: Dedicated IP Address · Shared IP Pool · Dedicated Sending IP
Quick definition
A dedicated IP is an internet protocol (IP) address used only by your email sends, so your reputation with inbox providers depends solely on your own behaviour. A shared IP is used by many senders through the same email service provider, so your deliverability depends partly on what everyone else sending from that pool is doing.
How it varies across Australia
Most small and mid-sized Australian senders sit on shared IPs by default through their email service provider and see no deliverability disadvantage. The businesses that benefit from a dedicated IP are the ones sending consistent, high volume with clean lists, where isolating reputation from a shared pool becomes worth the setup effort.
See deliverability benchmarks across Australian industries →What it actually means
Think of a shared IP like renting a warehouse dock alongside other tenants. If most tenants load their trucks properly, the whole dock gets waved through customs quickly. If one tenant keeps sending dodgy shipments, inspectors start checking everyone at that dock more carefully, including you. That's shared IP sending. Your deliverability is bundled with everyone else's behaviour on the same pool.
A dedicated IP is your own private dock. Nobody else's shipments affect how customs treats you. But there's a catch. Inbox providers like Gmail and Outlook build reputation over time by watching consistent sending patterns. A new dedicated IP has no history, so it needs a warm-up period of gradually increasing volume before providers trust it. Send too much too soon and you look like a new spammer, not a new dock.
This is where bounce rate, spam complaints and open rate all matter more on a dedicated IP, because there's no pool of other senders diluting a bad week. A single bad campaign shows up starkly in your own sender reputation.
Most email service providers default new customers to shared IPs for good reason. Unless you're sending very high, very consistent volume, the shared pool's aggregate reputation usually outperforms an unwarmed dedicated IP. Dedicated IPs make sense for large senders who want full control and can maintain the volume needed to keep the reputation warm.
A dedicated IP doesn't make you look better. It just makes sure nobody else can make you look worse, or better, than you actually are.
How it shows up
It shows up in deliverability reports when a business's open rate or spam complaint rate diverges sharply between a dedicated and shared setup after switching. On shared IPs, it shows up as an unexplained deliverability dip when a provider's monitoring flags another sender in the same pool for spam activity, which can temporarily affect everyone in that pool. On dedicated IPs, it shows up as a slow ramp period where sending too aggressively too early tanks the domain's early reputation with Gmail and Outlook.
The Australian context
Australian senders using major platforms like Mailchimp, Klaviyo or SendGrid are almost always on shared infrastructure unless they specifically pay for a dedicated IP add-on. For businesses sending to a largely Australian list, the bigger deliverability lever is usually authentication setup (SPF, DKIM, DMARC) rather than the IP question. Get authentication and list hygiene right first. The IP decision matters far less than most senders assume.
Where people get this wrong
Related terms
Common questions
Do I need a dedicated IP for my email marketing?
Only if you're sending high, consistent volume, typically several hundred thousand emails a month or more, and want full control over your sending reputation. Most small and mid-sized businesses get better deliverability staying on a reputable shared pool.
How long does it take to warm up a dedicated IP?
Usually two to four weeks of gradually increasing volume, starting small and ramping up while watching open rate, bounce rate and spam complaints. Rushing this period is the most common way new dedicated IPs get flagged early.
Can other senders on a shared IP hurt my deliverability?
Yes, if the pool includes senders with poor practices and the provider is slow to act. Reputable email service providers monitor shared pools closely, which is why choosing a good provider matters more than the IP type itself.
Does a dedicated IP improve open rates?
Not directly. Open rate depends on subject lines, sender reputation and list engagement, not IP type. A dedicated IP only helps if your own sending behaviour is strong enough to build a better reputation than the shared pool average.
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About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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