Common Network workflows
DNS answers come from one resolver at one moment and may be cached; a different resolver or location can return different records. Subnet and port tools describe address ranges and conventions, not which hosts or services are actually reachable.
Plan network and firewall settings
Calculate an IPv4 or IPv6 network and look up a service port. A port number does not prove which application is listening; confirm the process on the host.
- CIDR / Subnet Calculator — Subnet math for IPv4 and IPv6 CIDR blocks.
- Port Lookup — Find out what a port is for and whether to expose it.
- URL Parser — Break down a URL and edit its query parameters.
Check a domain's mail and name servers
Look up MX and NS records, resolve a hostname to its addresses and run a reverse PTR lookup to confirm that both directions agree.
- MX Lookup — Query DNS records through a resolver you choose.
- NS Lookup — Query DNS records through a resolver you choose.
- Hostname to IP — Query DNS records through a resolver you choose.
- IP to Hostname / PTR — Query DNS records through a resolver you choose.
DNS lookups leave this device
The domain or IP you enter is sent to the DNS-over-HTTPS resolver shown in the tool, only when you click Lookup. Calculators and references make no network requests.
Frequently asked questions
Can a port lookup identify an unknown network service?
It can identify common assignments and conventions, but applications can listen on arbitrary ports. Confirm the running process and protocol on the host rather than relying on the number alone.
Why do my DNS results differ from another tool?
Resolvers cache records for their TTL and some return location-specific answers. Compare resolvers, and check the authoritative name servers after a recent change.
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