Troubleshooting DNS problems

If one suspects a website has been compromised, don’t use a standard web browser to access the site as there could be zero-day malware on the site. Consider Terminal programs that don’t have JavaScript enabled like curl or lynx if necessary to browse the site, preferably from a VM or other isolated computing resource. These programs are also not immune from security vulnerabilities.

DNSViz helps visualize the DNS chain. Keep in mind DNS and nameserver updates can take minutes to hours to propagate.

macOS:

dscacheutil -q host -a name host.invalid

Linux / macOS / WSL:

dig +trace host.invalid

If the DNS entries seem valid, consider that the web hosting server (that sends the HTML files to browser) may be compromised.