Free URL shortener
Paste a long link, get a short f5i.org link to share, and see every click.
- Click tracking
- Traffic sources
- Devices
Example f5i.org/k7Xp2a · Free · an account is needed to see stats
Advertisement
All tools
30 tools in 6 groups.
Mail
7
- Email checkCheck MX, SPF, DKIM, DMARC and PTR records for a domain to find out why your mail lands in spam.
- DKIM generatorGenerate a DKIM key pair and TXT record in your browser. The private key never leaves your device.
- SPF record generatorBuild an SPF record for your domain and count DNS lookups so you stay within the limit of 10.
- DMARC record generatorBuild a DMARC record and a step-by-step path to block spoofed mail without losing real mail.
- Email signature generatorDesign a clean email signature for Gmail, Outlook and Apple Mail, then copy and paste it in.
- Blacklist checkCheck whether an IP or domain is listed on the spam blocklists that make receivers reject your email.
- Email header analyzerAnalyze email headers to see which servers a message passed through and where it was delayed.
DNS / Domain
4
- DNS lookupLook up A, MX, TXT, NS and other DNS records through the resolver of your choice to check a setup.
- DNS propagationCompare a DNS record across many resolvers to see whether your change has propagated.
- Domain WHOISRun a WHOIS lookup to see a domain’s expiry date, nameservers, registrar and transfer lock status.
- DNSSEC checkVerify that a domain’s DS and DNSKEY chain is valid so DNSSEC validation succeeds.
Website
5
- Basic SEO checkRun a basic on-page SEO check: title, description, H1, canonical tag and load speed.
- HTTP headersView the HTTP headers and status code of a URL to see how the web server responds.
- Redirect checkerFollow every 301/302 redirect from a URL to the final page and spot loops and long chains.
- Is this website up?Checked from our server in Vietnam: up, slow or down
- Who hosts this websiteProvider, country, CDN, DNS and email of a website
Network / IP
5
- IP WHOISLook up an IP address to see who owns the range, its ASN, country and WHOIS data.
- Ping & portPing a host with 4 ICMP packets and test one TCP port to see whether it responds.
- Reverse DNS (PTR)Look up the PTR (reverse DNS) record of an IP to see its hostname and check mail server setup.
- TracerouteTrace the path packets take from Vietnam to a host to spot where the delay starts.
- Subnet calculatorCalculate the network range, subnet mask, broadcast address and usable host count from a CIDR.
SSL / Certificates
5
- SSL checkCheck a domain’s SSL certificate: expiry date, CA chain and whether the name matches.
- SSL to PFX converterCombine a certificate, private key and CA bundle into a single .pfx file for Windows or IIS.
- CSR generatorGenerate a CSR and private key to order an SSL certificate, with the fields CAs expect.
- CSR & certificate decoderDecode a CSR or certificate to see its domain names, expiry date and issuer before you install it.
- Certificate key matcherCheck that a certificate, CSR and private key belong together before you install SSL.
Utilities
4
- What is my IPSee your public IP address to paste into a support ticket or add to a firewall allowlist.
- URL shortenerShorten links to f5i.org and track clicks, traffic sources and devices for each one.
- QR code generatorQR codes for links, Wi-Fi, contact cards and VietQR transfers
- Punycode converterConvert Unicode domain names to xn-- punycode and back so you can configure DNS correctly.