DNS Lookup

DNS propagation is the time it takes for a record change to be seen everywhere, and it is governed by the TTL on the record. Resolvers that cached the old value keep serving it until the TTL expires, which is often a few minutes to a few hours but can reach 24 to 48 hours for high TTLs. Lowering the TTL a day before a planned change makes the switch faster. During this window a lookup may show the new value from one resolver while another still returns the old one. To watch a record for changes over time, see WebPixie DNS monitoring.

To find the IP address of a website, look up its DNS address records:

• A record holds the IPv4 address
• AAAA record holds the IPv6 address

Enter the domain in the tool above and read the A and AAAA rows; a site can have several for load balancing. Keep in mind that sites behind a CDN or proxy return the provider address rather than the origin server. Once you have the address, you can work out its network and range with the IP Subnet Calculator.

SPF and DMARC are email authentication policies published as TXT records, and the tool above parses both for you:

• SPF lists the servers allowed to send mail for the domain, in a TXT record beginning with v=spf1
• DMARC tells receivers what to do with mail that fails checks, in a TXT record at _dmarc.yourdomain

Enter the domain above and read the parsed sections rather than decoding the raw TXT by hand. Misconfigured records are a common cause of mail landing in spam. To track these records and alert on changes, WebPixie DNS monitoring analyzes SPF, DMARC, and more.

A reverse DNS lookup (PTR lookup) finds the hostname associated with an IP address, the opposite of a normal forward lookup. It works through PTR records in a special reverse zone, and it is commonly used to verify mail servers, since many receivers reject mail from IPs with no matching reverse record. The tool above resolves reverse DNS for both IPv4 and IPv6 addresses. A forward record and its matching reverse record do not have to agree, and a mismatch is worth checking when you diagnose mail delivery. Not every IP has a PTR record, so an empty result is normal.

They answer different questions:

• a DNS lookup reads the records that make a domain work, such as A, MX, and TXT (where it points)
• a WHOIS lookup reads the domain registration, such as registrar, expiry date, and status (who owns it)

The tool above handles the DNS side. For registration data, use the Domain Lookup tool, which queries WHOIS and RDAP. Both are useful when you set up or investigate a domain, since a working domain needs correct records and a valid registration.

Different DNS servers can return different results mainly because of caching and propagation. Common reasons:

• each resolver caches a record until its TTL expires, so one may serve a new value while another holds the old
• some domains use geographic or load-balanced DNS that returns different addresses by location
• anycast and split-horizon setups add further variation

Querying a public resolver such as Google or Cloudflare gives a neutral view that bypasses your local cache. To catch unexpected changes over time, WebPixie DNS monitoring checks your records daily against the authoritative server, with public resolvers as fallback.