Why does a DNS change take time to propagate?

DNS records are cached by resolvers worldwide according to the record's TTL (time to live) value, measured in seconds. Until a cached record expires, resolvers serve the old value. Lowering a record's TTL before making a change reduces propagation time. The DNS propagation checker queries multiple global resolvers simultaneously so you can see which regions have picked up the new value.

What DNS record types can I look up?

The DNS lookup tool supports A (IPv4 address), AAAA (IPv6 address), CNAME (canonical name alias), MX (mail exchange), TXT (text records used for SPF, DKIM, and domain verification), NS (name servers), and SOA (start of authority) record types.

What does the SSL checker verify?

The SSL checker retrieves the certificate chain for a hostname and reports the subject, issuer, validity period (not-before and not-after dates), SANs (subject alternative names), and the certificate's serial number. It is useful for confirming that a certificate is installed correctly, checking expiry dates before renewal, and verifying that the correct certificate is served for a domain.

Why would an IP address appear on a blacklist?

IP addresses are added to blacklists when they are associated with spam, phishing, malware distribution, open proxies, or other abusive behaviour. Shared hosting IP addresses sometimes inherit a bad reputation from other tenants. The IP blacklist checker queries the most common DNSBL (DNS-based blackhole list) providers and reports which lists, if any, include the queried address.

Network & DNS Tools | DevToolsForYou

7 free browser-based tools

Network and DNS queries that previously required command-line tools or specialist software are available here as one-click browser utilities. Look up the geographic location and ISP for any IP address, resolve DNS records for any hostname, retrieve WHOIS registration data for domains, check MX records to debug email delivery, inspect SSL certificate details and expiry dates, verify that DNS changes have propagated across global resolvers, and check whether an IP address appears on common spam and abuse blacklists. These tools make live DNS queries from the server and return real-time results.

Free online network and DNS tools — IP address lookup, DNS lookup, WHOIS lookup, MX record checker, SSL certificate checker, DNS propagation checker, and IP blacklist checker.

IP Address Lookup

Look up geolocation, ISP, ASN, and network details for any IP address or domain — or detect your own IP instantly.

DNS Lookup

Query DNS records for any domain — A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, PTR, or all at once.

WHOIS Lookup

Look up registration details, ownership, nameservers, and expiry for any domain, IP address, or ASN.

DNS Propagation Checker

Check whether your DNS change has propagated across 10 global resolvers — see which ones have updated and which still serve the old record.

MX Record Checker

Check MX records, SPF, DMARC, and DKIM configuration for any domain — with an email security score.

SSL Certificate Checker

Inspect the full SSL/TLS certificate chain for any domain — validity, expiry, issuer, SANs, fingerprints, and key details.

IP Blacklist Checker

Check whether an IPv4 address is listed on any of 17 DNS-based blacklists used by spam filters and firewalls worldwide.

Frequently asked questions

Why does a DNS change take time to propagate?: DNS records are cached by resolvers worldwide according to the record's TTL (time to live) value, measured in seconds. Until a cached record expires, resolvers serve the old value. Lowering a record's TTL before making a change reduces propagation time. The DNS propagation checker queries multiple global resolvers simultaneously so you can see which regions have picked up the new value.
What DNS record types can I look up?: The DNS lookup tool supports A (IPv4 address), AAAA (IPv6 address), CNAME (canonical name alias), MX (mail exchange), TXT (text records used for SPF, DKIM, and domain verification), NS (name servers), and SOA (start of authority) record types.
What does the SSL checker verify?: The SSL checker retrieves the certificate chain for a hostname and reports the subject, issuer, validity period (not-before and not-after dates), SANs (subject alternative names), and the certificate's serial number. It is useful for confirming that a certificate is installed correctly, checking expiry dates before renewal, and verifying that the correct certificate is served for a domain.
Why would an IP address appear on a blacklist?: IP addresses are added to blacklists when they are associated with spam, phishing, malware distribution, open proxies, or other abusive behaviour. Shared hosting IP addresses sometimes inherit a bad reputation from other tenants. The IP blacklist checker queries the most common DNSBL (DNS-based blackhole list) providers and reports which lists, if any, include the queried address.