- 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 3191: ConServR SSL Proxy
Port 3191 is assigned by IANA to csvr-sslproxy (ConServR SSL Proxy).
3191
How csvr-sslproxy 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 3191 dangerous?
We have no specific security note for port 3191. Its risk depends on the program actually listening on it. General advice for vpn, tunnels & proxies services:
IANA registry entries for port 3191
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| csvr-sslproxy | 3191 | TCP, UDP | ConServR SSL Proxy | - | - |
// source: IANA service name and port number registry
Which program uses port 3191, and is it reachable?
Linux
sudo ss -ltnup 'sport = :3191' # process listening on 3191
sudo lsof -nP -i :3191macOS
sudo lsof -nP -i :3191
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3191 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 3191 netstat -ano | findstr :3191
From another machine
nmap -p 3191 -sV <host> sudo nmap -sU -p 3191 <host> nc -zv <host> 3191
Block it in the firewall
sudo ufw deny 3191/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 3191" -Direction Inbound -LocalPort 3191 -Protocol TCP -Action Block # Windows
What is port 3191 used for?
Port 3191 is assigned by IANA to csvr-sslproxy (ConServR SSL Proxy).
Is port 3191 TCP or UDP?
Port 3191 is registered for TCP and UDP.
Is it safe to open port 3191?
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 3191 is open?
On Linux run "ss -ltnup 'sport = :3191'", on macOS "lsof -nP -i :3191", and on Windows "netstat -ano | findstr :3191" to see the local process. From another machine, "nmap -p 3191 <host>" shows whether it is reachable.