001: the first loop works

 OpenPorts watches a domain from the outside and reports what it exposes: open ports, TLS certificates on their way out, mail records that let anyone spoof you, headers that give away the stack. The first full loop went end to end: add a domain, publish one TXT record to prove you own it, then the scanner runs. No record, no scan, one exception for the public test target Nmap itself runs for scanner builders. 

The scanner stays deliberately modest: one connect sweep over the hundred most likely ports, a TLS handshake to read the certificate, a few DNS lookups for spoofing protection, and three small HTTP checks. Nothing sends a payload, nothing probes services. A full scan takes under three seconds. 

Two real bugs worth writing down. First, the hand-assembled port list was just wrong, missing port 3389 entirely, so the single highest-severity finding in the whole catalog could never actually fire. A boring test that just checks a list of numbers felt like pure ceremony right up until it caught exactly that. 

Second, the test target’s port 80 turned out flaky in the worst way for a monitoring product: sometimes it answers fully, sometimes the connection opens but the request just hangs until timeout, and reported findings silently change between runs though nothing on the customer’s end did anything. Now recording exactly what the network said instead of pretending every check came back clean; confirming a change twice before reporting it is next. 

Architecture choices so far: a simple embedded database instead of a separate one to babysit, and one plain interval-based worker in the main process instead of real job infrastructure, the least moving parts that still survives a restart without double-scanning. What doesn’t work yet: no service identification on open ports, TLS only checked when the main web port answers, and only one scan at a time. 

Next: naming what’s running on each open port, scheduled rescans, and diffing between scans, since “this port showed up since yesterday” is the real product.