# Is It the Network? ping, curl -I and Ports

When a website or server doesn't answer, four quick checks find the broken link: ping asks whether the computer answers, curl -I whether the website does, ss or lsof which program is listening on a port, and dig which address a name points to.

![Cheat sheet for the lesson Is It the Network? ping, curl -I and Ports: When a website or server doesn't answer, four quick checks find the broken link: ping asks whether the computer answers, curl -I whether the website does, ss or lsof which program is listening on a port, and dig which address a…](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/4d1ae57bf0384d4c807d38edd9e6ac4a.webp)

- Category: Bash
- Level: Journeyman
- Tags: dig, dns, Domain Name, IP Address, linux, ping, port, unix
- Updated: November 10, 2026

Source: https://www.ask-codey.com/cheat-sheets/bash-network-checks-cheat-sheet