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+---
+title: "Port Scan"
+tags: [ "networking" ]
+repo: 'https://github.com/mrjackwills/havn/'
+---
+
+`havn` scans ports.
+It's not in many repos, but if you can `cargo install havn`.
+
+
+```sh
+havn -h
+havn -a
+domain=splint.rs
+havn -p 19-90 ${domain}
+```
+
+That last command doesn't work reliably, so increase the number of retries (`-r`), or decrease concurrent requests (`-c`).
+
+
+```sh
+havn -p 19-443 -r 6 ${domain}
+havn -p 1-1000 -c 500 -r 5 ${domain}
+```
+