Kodura Network Tools

Basic network troubleshooting, all in one place. Ping, traceroute, DNS lookups, port checks and path MTU discovery — the five things you reach for when something is wrong, without five separate apps and five separate subscriptions. NO ADS. NOTHING TO BUY. No banners, no upgrade prompts, no account, no subscription. Every tool is there the moment you open it. ONE TARGET, EVERY TOOL Type a host once and it carries across all five. A real diagnosis moves between them — ping gets nothing back, so you trace the path; the trace stops at hop nine, so you check whether DNS gave you the right address; then you see whether the port is even open. Retyping the hostname at every step is the friction that sends people back to a laptop. RESULTS THAT EXPLAIN THEMSELVES Most tools hand you a column of numbers and leave the interpretation to you. This one tells you what it means: • A hop showing * is usually a router configured not to reply, not a break in the path. If later hops answered, your traffic went straight through. • A host that ignores ping may be perfectly healthy. Plenty of servers and firewalls drop ICMP deliberately, so silence is not proof of anything. • Jitter is judged against the latency it varies around. Thirty milliseconds of variation is fine on a satellite link and terrible on a local one. • A port that refuses a connection is telling you something. A port that stays silent is what a firewall looks like — and those are different problems. PING Loss, round-trip time, and jitter, with the distribution drawn so you can see the shape of the variation rather than reading it out of a list. TRACEROUTE Every hop with its round-trip times and reverse DNS name, and a clear statement of where the path actually ended — as opposed to where a router simply declined to introduce itself. DNS LOOKUP A, AAAA, CNAME, MX, TXT, NS, SOA and PTR, against a resolver you choose — Cloudflare, Google, Quad9 or OpenDNS — rather than whichever one your device happens to be using. Asking two resolvers the same question and getting different answers is often the whole diagnosis. "No such name" and "the server failed" are reported as the different problems they are. PORT CHECK Common services by name, or any ports you type. Refused and silent are reported separately, and anything open that usually should not be — databases, remote desktop, SMB — is called out. PATH MTU The largest packet that survives the whole path, found by probing with the don't-fragment bit set. Worth knowing because an MTU mismatch produces the strangest fault in networking: small requests work and large ones hang. SSH connects then freezes on long output, a page loads but one image never finishes, a tunnelled connection is fine until somebody sends an attachment. It looks like an application problem, and the application is fine. Built by Kodura for network engineers, sysadmins and anyone who has been handed a laptop and asked why the internet is slow.