Port 4505 (SaltStack publisher)

Salt master publish port (minions subscribe here); 4506 is the request server.

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

What port 4505 is used for

Salt master publish port (minions subscribe here); 4506 is the request server.

Security: should port 4505 be open?

Do not expose to the internet. CVE-2020-11651/11652 let attackers take over exposed Salt masters and every minion; thousands were hit within days. Never expose 4505/4506.

IANA assignment

Port 4505 is in the registered range and has no IANA assignment. The usage above is unofficial but widespread.

Check what is listening on port 4505

Linux: is anything listening on TCP 4505?

sudo ss -tlnp 'sport = :4505'

Linux / macOS: which process owns the port

sudo lsof -nP -i :4505

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':4505 '

Windows (Command Prompt)

netstat -ano | findstr :4505

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4505 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 4505

From Windows

Test-NetConnection HOST -Port 4505

Block port 4505 in the firewall

ufw

sudo ufw deny 4505/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 4505 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 4505 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 4505' -Direction Inbound -Protocol TCP -LocalPort 4505 -Action Block

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