IP lookup
An IP lookup is the process of querying a database or service to retrieve information associated with a specific IP address, such as its approximate geographic location, the organisation it belongs to, its hosting provider, or its email sending reputation. Every device connected to the internet has an IP address, and an IP lookup reveals information about where that address is registered, what network it belongs to, and in the context of email, what reputation it has accumulated as a sending source.
In email marketing, IP lookup is most commonly used to check whether a sending IP address is listed on any major email blacklists, to verify the geographic location of IP addresses in deliverability reports, and to investigate unusual activity in email analytics, such as a sudden spike in opens from an unexpected location which may indicate bot activity. Free tools like MXToolbox allow you to check your IP’s blacklist status and retrieve basic network information in seconds.
For B2B marketers and marketing operations teams, IP lookup is a diagnostic tool rather than a day-to-day operational one. The most common use case is checking whether your sending IP has been listed on a blacklist when deliverability problems emerge unexpectedly. Understanding the IP ranges used by your email service provider is also useful context when interpreting email analytics data and filtering out automated bot activity from your engagement reports.
How do you look up an IP address?
Numerous free tools perform IP lookups. MXToolbox (mxtoolbox.com) is widely used in email marketing for checking IP reputation and blacklist status. WhatIsMyIPAddress.com and ipinfo.io provide geographic and network information for any IP address. For email-specific diagnostics, Google Postmaster Tools provides reputation data for your sending IPs and domains in relation to Gmail. Most of these tools require only entering the IP address in question and selecting the type of lookup you want to perform.
What information does an IP lookup return?
A typical IP lookup returns the approximate geographic location of the IP address, the organisation or internet service provider that owns the IP range, the associated domain name if any, the hosting provider for IP addresses assigned to servers, and in email-specific lookups, the reputation status against major blacklists. The geographic location returned is based on registration data and may not reflect the actual physical location of the device.
Why would I need to check the reputation of an IP address?
In email marketing, the sending reputation of your IP address affects whether your emails are delivered to the inbox or filtered as spam. Checking your IP’s reputation against major blacklists is a standard deliverability maintenance task. If your IP appears on a blacklist, emails sent from it may be blocked or filtered by mail servers that subscribe to that list. Checking IP reputation is also useful when investigating sudden drops in deliverability, as a blacklisting event often explains a rapid change in inbox placement rates.