Port 9000 (PHP-FPM / MinIO / SonarQube / Portainer)

Shared by several popular tools: PHP-FPM's FastCGI listener (when using TCP instead of a socket), the MinIO S3 API, SonarQube, and older Portainer versions.

Registered (user) port, 1024-49151 TCP Development tools Do not expose to the internet

What port 9000 is used for

Shared by several popular tools: PHP-FPM's FastCGI listener (when using TCP instead of a socket), the MinIO S3 API, SonarQube, and older Portainer versions.

Security: should port 9000 be open?

Do not expose to the internet. An exposed PHP-FPM port lets attackers run arbitrary PHP via FastCGI. Bind it to 127.0.0.1 or a Unix socket. For MinIO, change the default minioadmin credentials.

IANA assignment

Service nameProtoDescriptionAssigneeReference

cslistener TCP CSlistener David Jones -

cslistener UDP CSlistener David Jones -

Check what is listening on port 9000

Linux: is anything listening on TCP 9000?

sudo ss -tlnp 'sport = :9000'

Linux / macOS: which process owns the port

sudo lsof -nP -i :9000

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':9000 '

Windows (Command Prompt)

netstat -ano | findstr :9000

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 9000 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 9000

From Windows

Test-NetConnection HOST -Port 9000

Block port 9000 in the firewall

ufw

sudo ufw deny 9000/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 9000 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 9000 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 9000' -Direction Inbound -Protocol TCP -LocalPort 9000 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.