- Patch VPN gateways quickly: they are a top initial access target.
- Use certificates or MFA rather than shared secrets.
- Investigate unexpected tunnels and proxies: they are also attacker tools.
Port 2303: Proxy Gateway
Port 2303 is assigned by IANA to proxy-gateway (Proxy Gateway).
2303
How proxy-gateway works
VPN, tunnels & proxiesTraffic is wrapped in a tunnel between the two ends, so the network in between only sees the tunnel.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Registered (1024-49151)
- Category
- VPN, tunnels & proxies
Is port 2303 dangerous?
We have no specific security note for port 2303. Its risk depends on the program actually listening on it. General advice for vpn, tunnels & proxies services:
IANA registry entries for port 2303
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| proxy-gateway | 2303 | TCP, UDP | Proxy Gateway | - | - |
// source: IANA service name and port number registry
Which program uses port 2303, and is it reachable?
Linux
sudo ss -ltnup 'sport = :2303' # process listening on 2303
sudo lsof -nP -i :2303macOS
sudo lsof -nP -i :2303
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2303 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 2303 netstat -ano | findstr :2303
From another machine
nmap -p 2303 -sV <host> sudo nmap -sU -p 2303 <host> nc -zv <host> 2303
Block it in the firewall
sudo ufw deny 2303/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 2303" -Direction Inbound -LocalPort 2303 -Protocol TCP -Action Block # Windows
What is port 2303 used for?
Port 2303 is assigned by IANA to proxy-gateway (Proxy Gateway).
Is port 2303 TCP or UDP?
Port 2303 is registered for TCP and UDP.
Is it safe to open port 2303?
It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Patch VPN gateways quickly: they are a top initial access target.
How do I check if port 2303 is open?
On Linux run "ss -ltnup 'sport = :2303'", on macOS "lsof -nP -i :2303", and on Windows "netstat -ano | findstr :2303" to see the local process. From another machine, "nmap -p 2303 <host>" shows whether it is reachable.