DNS Lookup Tools
Query any public DNS record type, check whether a change has propagated across major public resolvers, validate DNSSEC, and look up WHOIS and reverse DNS.
Each lookup explains what the record does and flags common mistakes, such as an MX record that points at a CNAME, a missing CAA record, or a broken DNSSEC chain.
15 free dns tools
- A RecordIPv4 address for a domain
- AAAA RecordIPv6 address for a domain
- CNAME RecordDomain alias lookup
- MX RecordMail servers for a domain
- NS RecordAuthoritative nameservers
- TXT RecordArbitrary text records
- SOA RecordZone authority details
- CAA RecordAuthorized certificate issuers
- Propagation CheckerCheck a record across global resolvers
- WHOIS LookupRegistrar, creation/expiry dates, and nameservers
- DNSSEC CheckerCheck DNSSEC signing and chain-of-trust validation
- RDNS LookupReverse DNS (PTR) lookup for an IP address
- SRV RecordService records (priority, weight, port, target)
- DS RecordDNSSEC delegation signer records at the parent zone
- Zone Transfer TestCheck whether nameservers allow an AXFR transfer
Guides: Network Protocols
- IPv6 for People Who Know IPv4Address notation and the /64 rule, link-local and ULA and GUA, SLAAC vs DHCPv6, no NAT and what replaces it, NDP instead of ARP, dual-stack, and the firewall implications.
- 802.1Q VLANs ExplainedVLAN tags in the Ethernet frame, access vs trunk ports, the native VLAN, inter-VLAN routing, configuring tagged interfaces on Linux, and the security gotchas (VLAN hopping).
- VXLAN and Overlay NetworksWhy overlays exist, VXLAN encapsulation (VNI, VTEP, UDP 4789), MTU implications, multicast vs unicast/EVPN control planes, and how container/cloud networks use it under the hood.
- TCP Congestion Control BasicsSlow start, congestion avoidance, fast retransmit/recovery, the difference between loss-based (CUBIC) and model-based (BBR) control, bufferbloat, and picking an algorithm on Linux.
- VRRP and keepalived for Gateway/Service FailoverHow VRRP shares a virtual IP between routers, master election and priority, keepalived config for a floating VIP, adding health checks and LVS, and split-brain / ARP gotchas.
- DNS over TLS and DNS over HTTPSWhy plain DNS is a privacy and integrity problem, how DoT (port 853) and DoH (443) differ, where each fits, running a resolver with DoT upstream, and the enterprise visibility trade-off.
Checking a whole domain? The Super Scanner runs every DNS, email, website and security check at once and gives one score.