Every device connected to the internet has an IP address — the network-layer identifier that allows traffic to be routed to and from it. For developers, IP lookup tools come up constantly: verifying VPN behaviour, debugging geolocation features, testing rate limiting, investigating suspicious traffic, or simply checking what country a CI server appears to be in. The DevToolShack IP Lookup shows your current IP and full geolocation data instantly — or look up any IP address.
IPv4 vs IPv6
IP addresses come in two versions:
- IPv4 — the original format: four groups of numbers from 0–255, separated by dots. Example:
93.184.216.34. IPv4 provides about 4.3 billion unique addresses — a number the internet has long since exhausted. - IPv6 — the modern format: eight groups of four hexadecimal digits, separated by colons. Example:
2606:2800:220:1:248:1893:25c8:1946. IPv6 provides 340 undecillion addresses — effectively unlimited. Adoption is growing but IPv4 remains dominant for now.
Most devices have both. When you check your IP, you'll typically see whichever version was used for the connection to the lookup service.
What an IP Lookup Reveals
| Field | What It Means |
|---|---|
| IP Address | Your public-facing IP — what the internet sees |
| Country / City | Approximate geolocation based on IP registration data |
| ISP | Your Internet Service Provider or hosting company |
| ASN | Autonomous System Number — identifies the network operator |
| Hostname | Reverse DNS lookup of the IP address (if configured) |
| Timezone | Timezone inferred from geolocation data |
Developer Use Cases
Testing Geolocation Features
If your app shows different content by country (different pricing, legal notices, language defaults), use IP lookup to verify what country your server and test devices appear to be in — and confirm the geolocation logic works as expected.
VPN and Proxy Verification
After enabling a VPN, check your IP to confirm traffic is routing through the expected exit node. An IP lookup will show the VPN provider's ASN and the exit country, confirming the VPN is active and working.
Investigating Suspicious Traffic
When analysing access logs, looking up unfamiliar IP addresses reveals whether traffic comes from expected data centres, legitimate ISPs, hosting providers, known bot networks, or unusual geographic locations.
Rate Limiting and IP Banning
Before adding an IP to a blocklist, look it up. It might be a Googlebot crawler, a CDN egress node, or a shared NAT address — banning it could block legitimate traffic.
Firewall and Security Rules
Understanding CIDR notation is essential for writing IP-based firewall rules:
192.168.1.0/24 # All IPs from 192.168.1.0 to 192.168.1.255
10.0.0.0/8 # All IPs from 10.0.0.0 to 10.255.255.255
0.0.0.0/0 # All IPv4 addresses (be careful with this one)The number after the slash is the prefix length — how many bits of the address are fixed. /24 fixes the first 24 bits, leaving 8 bits (256 addresses) variable.
Private vs Public IP Addresses
Not all IP addresses are publicly routable. Private IP ranges are used within local networks and are never directly accessible from the internet:
10.0.0.0 – 10.255.255.255 (10.0.0.0/8)
172.16.0.0 – 172.31.255.255 (172.16.0.0/12)
192.168.0.0 – 192.168.255.255 (192.168.0.0/16)
127.0.0.0 – 127.255.255.255 (loopback — localhost)If your IP lookup shows one of these, you're checking from a device behind NAT — your public IP is the address of your router or gateway, not the device itself.
Getting Your IP Programmatically
# The fastest way — plain text response
curl https://api.ipify.org
# With JSON
curl https://api.ipify.org?format=json
# IPv6 specifically
curl https://api6.ipify.org
# Full geolocation data
curl https://ipapi.co/json/// Fetch your public IP in JavaScript
const response = await fetch('https://api.ipify.org?format=json');
const { ip } = await response.json();
console.log(ip); // "93.184.216.34"