Network Tools

Calculate download times and bandwidth requirements. Convert between Mbps, MBps, and estimate transfer times for files.

Calculate the bandwidth delay product and the TCP window size a link needs to reach full throughput, and see why a fast high latency link delivers a fraction of its capacity by default.

Calculate transfer time, monthly data usage and required bandwidth, without the bits-and-bytes confusion.

Generate CAA records restricting certificate issuance to named authorities, with account and validation method pinning, wildcard control and an incident report address.

Calculate the recording storage and network bandwidth a camera system needs from resolution, frame rate, codec and retention, with motion recording and RAID overhead accounted for.

Merge a list of CIDR prefixes into the smallest equivalent set, removing duplicates and overlaps and combining adjacent blocks, to shrink firewall rules and routing tables.

Convert CIDR notation to a first and last address, host count and netmask, and check whether two blocks overlap.

A new tool extracted from the codebase.

Size a DHCP pool from device count and churn, choose a lease time that balances address reuse against broadcast load, and see when the scope will exhaust.

Analyze DNS records (TXT, SPF) for security gaps.

Check how a DNS record resolves from resolvers around the world and understand why changes appear at different times in different places.

Check how your DNS records are propagating across global servers (Google, Cloudflare, Local).

Build correctly formatted DNS records in zone file syntax, with the trailing dot rules, TXT string splitting and CNAME restrictions that cause most record errors.

Plan the TTL reductions before a DNS change and the timeline for a migration cutover, including how long stale answers persist and what ignores your TTL entirely.

Validate a DNS zone file for syntax errors, missing trailing dots, CNAME conflicts, SOA field problems and the record combinations that resolvers handle inconsistently.

Optimize and analyze firewall rules for conflicts and redundancies.

Evaluate firewall rules for over-permissive exposure.

Inspect HTTP response headers for any URL. Check security headers, caching, content type, and redirects.

Inspect raw HTTP response headers, status codes, and redirect counts.

Sort a list of IPv4 addresses in correct numeric order (not alphabetical), ascending or descending, with de-duplication and invalid-line detection. Free, private.

Convert an arbitrary IP address range into the minimum set of CIDR prefixes that covers it exactly, and convert prefixes back to a range, for firewall rules and access lists.

Check an IP address against reputation signals and blocklists, and understand why an address gets listed and how to get it delisted.

Check a list of subnets for overlaps, containment and duplicates before they collide in a VPN, a VPC peering or a network merge, and see which specific addresses conflict.

Convert an IPv4 address between dotted decimal, binary, hexadecimal and 32-bit integer, and see why subnetting makes sense in binary.

Validate an IPv6 address and output expanded and compressed representations.

Expand and compress IPv6 addresses, calculate subnet ranges and counts from a prefix, and plan an allocation using the /64 and /48 conventions that IPv6 addressing assumes.

Generate valid random MAC addresses for testing, with correct handling of the locally administered and multicast bits.

Look up the manufacturer behind a MAC address from its OUI prefix, and identify locally administered and randomised addresses.

Calculate the correct MTU and TCP MSS for a path with tunnels, VLAN tags or PPPoE, and understand why a connection completes its handshake and then hangs on the first large transfer.

View your public IP address and user agent information.

Convert availability percentages into real downtime, calculate the availability of series and parallel components, and see what redundancy actually buys once shared failure modes are included.

Estimate round-trip time between two points from distance, transmission medium and router hops, and see what that RTT costs in TCP and TLS handshakes.

Plan network segmentation strategies for zero trust architecture.

Calculate OSPF interface costs from bandwidth and reference bandwidth, compare path totals, and fix the default that makes every link above 100 Mbit/s indistinguishable.

Calculate how packet loss affects TCP throughput, file transfer time, voice quality and application requests, and see why a loss rate that looks negligible is not.

Calculate round-trip time, estimate latency impact on applications, and understand network performance metrics.

Calculate whether a PoE switch can power its devices, accounting for cable length losses, the difference between what the switch sources and the device receives, and headroom for failover.

Analyze which ports are exposed and their security implications.

Understand risks of specific open ports.

Check which common ports respond on a host and understand what each exposed service means. Scan only systems you are authorised to test.

Allocate link bandwidth across traffic classes with the right DSCP markings and queueing behaviour, and generate the policy map, checking the constraints that make a QoS design work.

Calculate rack power draw, heat output in BTU per hour, the circuits required with A and B feed redundancy, and the cooling capacity a room needs.

Generate random IPv4 or IPv6 addresses for testing, sample data and tutorials, with an option for public-only (non-reserved) ranges. Free, private, instant.

Find domains hosted on a specific IP address.

Analyze X-Forwarded-For and other headers.

Calculate spanning tree port costs under the legacy and long path cost methods, work out which bridge wins the root election, and see why the default cost table breaks above 10 Gbit/s.

Analyze SSL certificates for chain issues, expiry dates, and signature algorithms.

Calculate subnet masks, network and broadcast addresses, usable host ranges and CIDR notation for IPv4. Runs entirely in your browser.

A complete CIDR subnet cheat sheet mapping /0–/32 prefixes to subnet masks, wildcard masks, and usable host counts. Filter instantly. Free reference, private.

Plan a network by splitting a block into right-sized subnets with VLSM, and see exactly how many addresses each one wastes.

Check TLS cipher suite strength and security configurations.

Check client-server compatibility for TLS versions.

Paste traceroute or MTR output to see where latency is actually introduced, which hops are misleading, and why asterisks and a latency spike in the middle usually mean nothing.

Calculate the bandwidth a video stream needs at each quality level, size an adaptive bitrate ladder, and estimate concurrent viewer capacity and CDN egress cost.

Divide a network into subnets of different sizes using variable length subnet masking, allocated largest first so the address space is used efficiently and no ranges overlap.

Calculate the real bandwidth a VoIP deployment needs, including the protocol overhead that frequently exceeds the audio payload itself, plus jitter buffer and QoS guidance.

Instantly see your public IP address, location, ISP, and connection details.

Look up domain registration, registrar, nameservers and expiry dates, and understand what GDPR redaction removed from WHOIS records.

Plan WiFi channel assignments across access points, see which channels overlap, and understand why wider channels reduce throughput in dense deployments rather than increasing it.

Generate matching WireGuard server and client configurations with correct AllowedIPs, MTU, keepalive and firewall rules, and understand the routing rule that makes AllowedIPs different from an access list.