Free Tools
Free network, DNS and server tools
25 tools we use ourselves running a hosting network. Free, no sign-up, and no tracking of what you look up.
IP & Network
Subnet CalculatorNetwork, broadcast, usable range and mask for any IPv4 or IPv6 CIDR.What Is My IPYour public IP address, reverse DNS, network and ASN.IP & ASN LookupWhich network owns an IP: ASN, name, prefix, country and registry.Port LookupWhat runs on a TCP or UDP port, and whether it should be open.MTU & MSS CalculatorWork out MTU and TCP MSS through VLANs, PPPoE, VXLAN and VPN tunnels.
DNS
Email Authentication
Security & Abuse
SSL Certificate CheckerExpiry, issuer, chain, names and TLS version for any HTTPS site.IP Reputation CheckerCheck an IP against spam blocklists and threat feeds at once.Firewall Rule GeneratorGenerate iptables, nftables and UFW rules for common server set-ups.Abuse Report GeneratorWrite a clear abuse report another network will actually act on.
VPS & Linux
Chmod CalculatorLinux file permissions in octal and symbolic form, both ways.Cron Expression GeneratorBuild a crontab schedule and see it in plain English with next run times.VPS Cost CalculatorMonthly and yearly hosting cost, with IPs, bandwidth, storage and licences.VPS RAM CalculatorHow much memory a server needs for its OS, apps, databases and caches.Linux Command GeneratorReady-to-run commands for disks, networking, services, logs and diagnostics.Disk Space & RAID CalculatorConvert storage units and work out usable space for RAID and ZFS.SSH Key GeneratorCommands to create an SSH key on your own machine and install it safely.Docker Compose GeneratorStarter compose.yaml files for common stacks, with safe defaults.Nginx Config GeneratorServer blocks for reverse proxies, static sites and PHP, with HTTPS.
Built by the people behind Frabs
Frabs stops spam, scans and floods leaving hosting providers' VMs, before the abuse report arrives.