HTTPfy

Port 4004 (pxc-roid)

IANA assigns port 4004 to pxc-roid.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
pxc-roid TCP pxc-roid - -
pxc-roid UDP pxc-roid - -

Check what is listening on port 4004

Linux: is anything listening on TCP 4004?
sudo ss -tlnp 'sport = :4004'
Linux: UDP 4004
sudo ss -ulnp 'sport = :4004'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4004
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4004 '
Windows (Command Prompt)
netstat -ano | findstr :4004
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4004 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4004
From Windows
Test-NetConnection HOST -Port 4004
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4004

Block port 4004 in the firewall

ufw
sudo ufw deny 4004/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4004 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4004 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4004' -Direction Inbound -Protocol TCP -LocalPort 4004 -Action Block
ufw
sudo ufw deny 4004/udp
iptables
sudo iptables -A INPUT -p udp --dport 4004 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4004 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4004' -Direction Inbound -Protocol UDP -LocalPort 4004 -Action Block

Related ports

4002pxc-spvr-ft4003pxc-splr-ft4005pxc-pin4006pxc-spvr

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.