> For the complete documentation index, see [llms.txt](https://csbygb.gitbook.io/pentips/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://csbygb.gitbook.io/pentips/networking-protocols-and-network-pentest/unknown-ports.md).

# Useful tips when you find unknown ports

## Banner grabbing with nc

* `nc IP PORT` example: `nc 10.10.10.10 1234`