HTTPfy

Port 2303 (proxy-gateway)

IANA assigns port 2303 to proxy-gateway: Proxy Gateway.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
proxy-gateway TCP Proxy Gateway Paul Funk -
proxy-gateway UDP Proxy Gateway Paul Funk -

Check what is listening on port 2303

Linux: is anything listening on TCP 2303?
sudo ss -tlnp 'sport = :2303'
Linux: UDP 2303
sudo ss -ulnp 'sport = :2303'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2303
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2303 '
Windows (Command Prompt)
netstat -ano | findstr :2303
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2303 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2303
From Windows
Test-NetConnection HOST -Port 2303
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2303

Block port 2303 in the firewall

ufw
sudo ufw deny 2303/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2303 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2303 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2303' -Direction Inbound -Protocol TCP -LocalPort 2303 -Action Block
ufw
sudo ufw deny 2303/udp
iptables
sudo iptables -A INPUT -p udp --dport 2303 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2303 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2303' -Direction Inbound -Protocol UDP -LocalPort 2303 -Action Block

Related ports

2301cpq-wbem2302binderysupport2304attachmate-uts2305mt-scaleserver

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