Your public IP address is the identifier that every server on the internet sees when your device makes a connection. For email administrators and marketers, knowing your public IP is essential -- it is the address that mail servers, blocklists, and reputation systems associate with your sending activity. This tool displays your current public IP address along with associated network and geolocation details.
Your Public IP vs. Private IP
Most devices operate behind a router or firewall that uses Network Address Translation (NAT, RFC 3022). Your device has a private IP address on the local network (typically in the 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16 ranges), while the router presents a single public IP to the internet.
This distinction matters for email. When you send email through an SMTP server, the receiving server sees the public IP of your mail server, not your workstation's private address. If you run your own mail infrastructure, the public IP of your SMTP server is what accumulates reputation and appears in email headers.
What This Tool Shows
IPv4 Address
Your primary public IPv4 address as seen by our server. This is the address most commonly used for email sending and reputation tracking.
IPv6 Address
If your network supports IPv6, the tool also displays your IPv6 address. Dual-stack configurations are increasingly common, and some mail servers preferentially connect over IPv6 when both protocols are available. Major providers including Gmail support IPv6 for both sending and receiving.
ISP and Network
The tool identifies your Internet Service Provider and the Autonomous System Number (ASN) associated with your IP. This information helps you understand how your IP is categorized by reputation systems. Residential ISPs, commercial hosting providers, and dedicated email service providers are treated differently by receiving mail servers.
Geolocation
Approximate geographic location based on your IP's registration data. This typically includes country, region, and city. The accuracy varies -- data center IPs usually resolve to the facility's registered location, while residential IPs may be accurate to the city or regional level.
Why Your IP Matters for Email
Reputation Is Per-IP
Email reputation systems evaluate sending behavior at the IP level. If your IP has been used to send spam -- whether by you, a previous tenant, or a compromised device on a shared network -- that history follows the IP. Check your IP's current reputation status with our IP Reputation tool.
Blocklist Monitoring
DNS-based blocklists (DNSBLs) list IP addresses associated with spam, malware, or other abuse. If your public IP appears on a major blocklist like Spamhaus SBL, Spamhaus PBL, Barracuda, or SORBS, your email will be rejected or filtered by any receiving server that queries those lists.
Regularly checking your IP against blocklists is a baseline operational practice. Our IP Reputation tool checks multiple lists simultaneously.
SPF Authorization
Your SPF record (RFC 7208) specifies which IP addresses are authorized to send email on behalf of your domain. If your public IP changes -- common with residential ISPs or when switching hosting providers -- your SPF record must be updated to include the new address. Sending from an IP not listed in your SPF record causes SPF failures.
Reverse DNS Requirements
Legitimate mail servers must have a PTR record that maps their IP address back to a hostname, and that hostname must resolve forward to the same IP. This forward-confirmed reverse DNS (FCrDNS) is checked by Gmail, Outlook, Yahoo, and virtually every other major mailbox provider. Without it, your email is significantly more likely to be rejected or filtered.
How to Use This Tool
Simply load this page. Your public IP address is detected automatically and displayed along with network details. No input is required and no data is stored. The tool is free and works on any device.
FAQ
What is my IP address and why does it matter?
Your IP address is the unique numerical identifier assigned to your device or network by your Internet Service Provider, and it is visible to every server you connect to online. For email, your sending IP is what mailbox providers use to track your reputation, check blocklists, and evaluate deliverability. You can see your current public IP by loading our What Is My IP tool, and then check its reputation with the IP Reputation tool.
What is the difference between IPv4 and IPv6?
IPv4 addresses are 32-bit numbers written as four decimal octets (e.g., 192.0.2.1), providing roughly 4.3 billion unique addresses. IPv6 addresses are 128-bit numbers written in hexadecimal (e.g., 2001:db8::1), offering a vastly larger address space. Major email providers including Gmail support both protocols, and dual-stack configurations where servers use both IPv4 and IPv6 are increasingly common.
Can websites see my IP address?
Yes, every website and server you connect to can see your public IP address -- it is a fundamental part of how internet communication works. Your IP is included in the TCP connection and is logged by web servers, email servers, and other online services. For email specifically, your sending server's IP appears in the message headers and is checked against blocklists and reputation databases by every receiving mail server.
What is the difference between a public and private IP address?
A private IP address is used within your local network (typically in ranges like 10.0.0.0/8 or 192.168.0.0/16) and is not visible on the internet. A public IP address is assigned by your ISP and is the address that external servers see when you connect. Your router uses Network Address Translation (NAT) to map traffic between your private and public addresses. For email infrastructure, only the public IP of your mail server matters for reputation and deliverability.
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