HTTPfy

Port 3003 (cgms)

IANA assigns port 3003 to cgms: CGMS.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cgms TCP CGMS Corey Clinton -
cgms UDP CGMS Corey Clinton -

Registry dates for this port: registered 2011-02-02.

Check what is listening on port 3003

Linux: is anything listening on TCP 3003?
sudo ss -tlnp 'sport = :3003'
Linux: UDP 3003
sudo ss -ulnp 'sport = :3003'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3003
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3003 '
Windows (Command Prompt)
netstat -ano | findstr :3003
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3003 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3003
From Windows
Test-NetConnection HOST -Port 3003
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3003

Block port 3003 in the firewall

ufw
sudo ufw deny 3003/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3003 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3003 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3003' -Direction Inbound -Protocol TCP -LocalPort 3003 -Action Block
ufw
sudo ufw deny 3003/udp
iptables
sudo iptables -A INPUT -p udp --dport 3003 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3003 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3003' -Direction Inbound -Protocol UDP -LocalPort 3003 -Action Block

Related ports

3001origo-native3002exlm-agent, remoteware-srv3004csoftragent3005geniuslm

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