- Answer only the networks that need the service (no open resolvers, relays or reflectors).
- UDP services can be abused for DDoS amplification: rate-limit or block them at the edge.
- Disable legacy test services that have no use in production.
Port 11171: Surgical Notes Security Service Discovery (SNSS)
Port 11171 is assigned by IANA to snss (Surgical Notes Security Service Discovery (SNSS)).
11171
How snss works
Network servicesThe client sends a request to port 11171 and the snss service answers.
- Transport
- 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
- Network services
Is port 11171 dangerous?
We have no specific security note for port 11171. Its risk depends on the program actually listening on it. General advice for network services services:
IANA registry entries for port 11171
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| snss | 11171 | UDP | Surgical Notes Security Service Discovery (SNSS) | - | 2010-12-24 |
| - | 11171 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 11171, and is it reachable?
Linux
sudo ss -ltnup 'sport = :11171' # process listening on 11171
sudo lsof -nP -i :11171macOS
sudo lsof -nP -i :11171
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 11171 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 11171 netstat -ano | findstr :11171
From another machine
nmap -p 11171 -sV <host> sudo nmap -sU -p 11171 <host> nc -zv <host> 11171
Block it in the firewall
sudo ufw deny 11171/udp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 11171" -Direction Inbound -LocalPort 11171 -Protocol UDP -Action Block # Windows
What is port 11171 used for?
Port 11171 is assigned by IANA to snss (Surgical Notes Security Service Discovery (SNSS)).
Is port 11171 TCP or UDP?
Port 11171 is registered for UDP.
Is it safe to open port 11171?
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. Answer only the networks that need the service (no open resolvers, relays or reflectors).
How do I check if port 11171 is open?
On Linux run "ss -ltnup 'sport = :11171'", on macOS "lsof -nP -i :11171", and on Windows "netstat -ano | findstr :11171" to see the local process. From another machine, "nmap -p 11171 <host>" shows whether it is reachable.
Other network services ports
:53 DNS tcp · udp · moderate risk :135 MS RPC tcp · udp · high risk :123 NTP udp · tcp · moderate risk :67 DHCP server udp · tcp · moderate risk :111 rpcbind tcp · udp · high risk :9100 Raw printing (JetDirect) tcp · udp · high risk :631 IPP / CUPS tcp · udp · high risk :5353 mDNS udp · tcp · moderate risk