Free IT and Network Tools
42 Free Tools
Tools for IT support and anyone who looks after a website or a mailbox. Check your IP address and internet speed, look up DNS records, test whether a port is open, check an SSL certificate or a site's security headers, and see whether a mail server is on a blacklist. There are also calculators for subnets, CIDR and IPv6, and generators for SPF, DKIM and DMARC records. Checks that need the internet run on our small server on Cloudflare's network.
IP Address CheckerSee your public IP address, location and internet provider.Internet Speed TestTest your internet speed: download, upload, ping and jitter, measured to the nearest Cloudflare data centre.Download Speed TestTest your download speed — how fast your connection can receive data — plus ping and jitter.Upload Speed TestTest your upload speed — how fast you can send files, photos and video calls — plus ping and jitter.DNS LookupLook up A, AAAA, CNAME, MX, NS, TXT and SOA records for any domain.DNS Record CheckerCheck a domain’s DNS setup in one go: name servers, website and email records, SPF, DMARC, CAA and DNSSEC.DNS Propagation CheckerCheck whether a DNS change has reached the big public DNS resolvers — Cloudflare, Google, Quad9, OpenDNS and 8 more.DNS Speed TestFind the fastest public DNS service for your connection: Cloudflare, Google, Quad9, AdGuard, OpenDNS and NextDNS.Ping TestCheck if a website or server is up and how fast it answers. We connect to it several times and time each try.Port CheckerCheck if a port is open on a server, as seen from the internet.SSL CheckerCheck a website’s SSL certificate: who issued it, the names it covers, when it expires and whether the chain is complete.SSL Certificate Expiry CheckerCheck when the SSL certificates of up to 10 websites expire, sorted with the soonest first.Website Uptime CheckerIs a website down, or is it just you? Check it now, or keep checking every few minutes while this page is open.Website Response Time CheckerMeasure how fast a website answers: time to first byte over several requests, and the full page download.HTTP Status CheckerSee the HTTP status code of any page (200, 301, 404…), follow every redirect, and read the response headers.HTTP Headers CheckerSee all the HTTP headers a website sends, with a security grade for HSTS, CSP, X-Frame-Options and more.Redirect CheckerFollow every redirect of a web address step by step, and check that http, https, www and non-www all end at one address.WHOIS LookupSee who a domain is registered with, when it was registered and when it expires. Works for IP addresses too.Domain IP LookupFind the IP addresses of a domain, who owns them, which country they’re in, and which hosting or CDN it uses.Reverse DNS LookupFind the host name of an IP address (PTR record) and check that it points back to the same IP — important for mail servers.ASN LookupFind the network (ASN) behind an IP address or domain — owner, country and IP range — or look up an AS number.IP Blacklist CheckerCheck if an IP address or mail server is on spam blacklists (DNSBLs) like Spamhaus, SpamCop and Barracuda.IPv4/IPv6 Compatibility CheckerCheck whether a website, its DNS and its email work over IPv6 as well as IPv4 — and whether your own connection has IPv6.MX Record CheckerCheck a domain’s mail servers (MX records): priorities, IP addresses, email provider and common mistakes.TXT Record CheckerSee all TXT records of a domain explained: SPF, DMARC, DKIM and verification codes for Google, Microsoft and others.SPF, DKIM & DMARC CheckerCheck a domain's email security records — SPF, DKIM, DMARC and MX — and get plain-English fixes for anything wrong.SPF Record GeneratorBuild a correct SPF record for your domain: tick your email services, add your servers, and copy the DNS record.DMARC GeneratorCreate a DMARC record for your domain: choose the policy and where reports go, then copy it into your DNS.DKIM Record GeneratorCreate a DKIM key pair and the DNS record for it — made in your browser, so the private key never leaves your device.Email Header AnalyzerPaste email headers to see if SPF, DKIM and DMARC passed, where the message really came from, and where it was delayed.MAC Address LookupFind the maker of a network card or device from its MAC address, using the official IEEE list. Paste several to check them all.MAC Address FormatterReformat MAC addresses between colons, hyphens and Cisco dots, upper or lower case — many at once — and see what type of address each one is.Subnet CalculatorCalculate the network, masks, broadcast and host range for any IPv4 subnet.IPv4 CalculatorConvert an IPv4 address to decimal, hex and binary, see what kind of address it is, and add a /prefix to see its network.IPv6 CalculatorExpand or shorten an IPv6 address, see its type, and work out the range and size of any IPv6 prefix.IP to Decimal ConverterConvert an IP address to a decimal number, hex or binary — and a number back to an IP. IPv4 and IPv6, one or many at once.CIDR CalculatorTurn a CIDR block into an IP range, a range into CIDR blocks, merge a list of blocks, or check if an IP is inside. IPv4 and IPv6.User-Agent CheckerSee your browser, version, operating system and device as websites see them, and decode any user-agent string.Network Speed CalculatorWork out how long a download or upload takes, what speed you need, or how much data moves in a given time.Chmod CalculatorWork out Linux file permissions: tick boxes to get the number (like 755) and the rwx letters, or type either one.Cron Expression ExplainerTurn a cron schedule like 0 9 * * 1-5 into plain English and see exactly when it will run next.Cron Expression GeneratorBuild a cron schedule by picking when it should run — every few minutes, daily, weekdays, monthly — and get the expression, a plain-English check and the next run times.
Guides
- What Is a Hash? SHA-256 and File Checks Explained Simply
- What Is My IP Address? IPv4 vs IPv6 Explained
- DNS Records Explained: A, AAAA, CNAME, MX, TXT and More
- How to Check if a Port Is Open (and What the Results Mean)
- Subnetting Made Simple: CIDR, Subnet Masks and Usable Hosts
- SPF, DKIM and DMARC Explained: How to Stop Email Spoofing
- How SSL/TLS Certificates Work, and How to Check One Before It Expires
- How to Test Your Internet Speed Properly (and What the Numbers Mean)
- Cron Expressions Explained: Read and Write Schedules Without Mistakes
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