Check an IP address
See how your IP connects to a hostname
Enter an IP address to check its reverse and forward DNS records.
- IP address We look up the PTR record for your IP address.
- PTR hostname We find the hostname associated with your IP.
- Forward IP We then check the hostname's A/AAAA record to confirm it points back to your IP.
Understand reverse DNS
Reverse DNS uses a PTR record to map an IP address to a hostname. This check then compares that hostname with the forward address. Some mail systems look at the comparison. A match shows that the two sides agree. It does not guarantee email delivery.
What does a match mean?
A match means at least one PTR hostname returns the original IP address. IPv4 is compared with A records, and IPv6 with AAAA records. When several PTR records exist, one verified hostname is enough.
Who can change a PTR record?
A PTR record is usually changed by the provider that assigned the IP address. A and AAAA records are changed by the DNS administrator for the hostname. Confirm the intended hostname before changing either side.
Does this check email delivery?
No. The check shows whether reverse and forward DNS agree. It does not guarantee inbox delivery, and a mismatch is not, by itself, a vulnerability.