POST AI agent ready /v1/ip/reverse

Reverse DNS API - Resolve IP to Hostname (PTR Record)

Performs a reverse DNS lookup on an IP address and returns PTR records. Useful for identifying the hostname associated with an IP.

Endpoint

Code examples

curl -X POST https://api.botoi.com/v1/ip/reverse \
  -H "Content-Type: application/json" \
  -d '{"ip":"8.8.8.8"}'

When to use this API

Verify email sender infrastructure

When processing inbound email, resolve the sending server IP to its PTR record. Compare the hostname against the HELO/EHLO identity to confirm the sender is who they claim to be, reducing spam and spoofing.

Identify server owners in log analysis

Parse web server access logs and resolve high-traffic IPs to their PTR hostnames. Quickly determine whether traffic spikes come from known crawlers (like googlebot or bingbot) or unknown sources that need investigation.

Network troubleshooting and traceroute annotation

Annotate each hop in a traceroute with its PTR hostname to make network path analysis more readable. Hostnames like "ae-1.r01.snjsca04.us.bb.gin.ntt.net" tell you the provider, location, and router role at a glance.

Frequently asked questions

What is a PTR record?

A PTR (pointer) record maps an IP address back to a hostname. It is the reverse of an A record. PTR records are stored in the in-addr.arpa zone for IPv4 addresses.

Why might an IP return no PTR records?

Many IP addresses, especially those on residential ISPs or cloud providers, do not have PTR records configured. The network operator must explicitly create PTR records for their IP space.

How fast are reverse DNS lookups?

Typical response times are 10-50ms. The query_time_ms field in the response tells you the exact DNS resolution time for each request.

Can I use this to verify if an IP belongs to Google?

Yes. Google-owned IPs typically resolve to hostnames ending in google.com or googleusercontent.com. Check the PTR record and then do a forward lookup to confirm it matches.

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