What uses port 8443
Port 8443 is the HTTPS counterpart of 8080: Tomcat’s default TLS port, and common for admin consoles (UniFi, Plesk, VMware), Kubernetes dashboards and services running alongside a web server on 443. Browsers need the port in the URL: https://host:8443/.
Should port 8443 be open to the internet?
Restrict access. Only open this port to known networks or users, for example your office IP, a VPN or behind authentication.
Check what is listening on port 8443
sudo ss -ltnp 'sport = :8443'sudo lsof -nP -iTCP:8443 -sTCP:LISTENGet-NetTCPConnection -LocalPort 8443 -State Listen
netstat -ano | findstr :8443No output means nothing is listening. If a service should be, check that it is running and which address it binds to: 127.0.0.1 only accepts local connections, 0.0.0.0 or :: accepts them on every interface.
Fix “address already in use” on port 8443
Another process already holds the port. Find it with the commands above, then stop that service properly, or end the process:
sudo kill $(sudo lsof -t -iTCP:8443 -sTCP:LISTEN)Stop-Process -Id (Get-NetTCPConnection -LocalPort 8443 -State Listen).OwningProcessAllow port 8443 from trusted networks only
The examples allow 8443 only from 10.0.0.0/8; replace it with your own private network, office IP or VPN range.
sudo ufw allow from 10.0.0.0/8 to any port 8443 proto tcp
# Close it again:
sudo ufw delete allow from 10.0.0.0/8 to any port 8443 proto tcpsudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="10.0.0.0/8" port port="8443" protocol="tcp" accept'
sudo firewall-cmd --reloadNew-NetFirewallRule -DisplayName "HTTPS alternate 8443/TCP" -Direction Inbound -Protocol TCP -LocalPort 8443 -Action Allow -RemoteAddress 10.0.0.0/8On AWS, Google Cloud and Azure, also allow the port in the security group or network firewall rules; host firewalls and cloud firewalls are separate.
Test port 8443 from another machine
nc -zv example.com 8443Test-NetConnection example.com -Port 8443Related ports
- Port 443 (HTTPS): the default port for HTTPS, encrypted web traffic.
- Port 8080 (HTTP alternate): the most common alternate HTTP port, used by proxies, app servers and dev tools.
More web ports
80 (HTTP) . See all ports in the port lookup.
Sources
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Frequently asked questions
What is port 8443 used for?
Port 8443 is a common alternate HTTPS port. Port 8443 is the HTTPS counterpart of 8080: Tomcat’s default TLS port, and common for admin consoles (UniFi, Plesk, VMware), Kubernetes dashboards and services running alongside a web server on 443. Browsers need the port in the URL: https://host:8443/.
Is it safe to open port 8443?
Only open this port to known networks or users, for example your office IP, a VPN or behind authentication. Allow it only from the networks that need it, as in the firewall examples on this page.
How do I check if port 8443 is open?
On the server, list listening sockets with "sudo ss -ltnp 'sport = :8443'" on Linux or "sudo lsof -nP -i :8443" on macOS. From another machine, run "nc -zv host 8443" or, on Windows, "Test-NetConnection host -Port 8443". Connection refused means nothing is listening; a timeout means a firewall is dropping the traffic.