- Restrict management and monitoring protocols to the monitoring network.
- Replace community strings and default credentials.
- Send logs over TLS.
Port 561:
Port 561 is assigned by IANA to monitor ().
561
How monitor works
Monitoring & loggingThe monitoring server collects metrics, alerts or logs from devices over port 561.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Well-known (0-1023)
- Category
- Monitoring & logging
Is port 561 dangerous?
We have no specific security note for port 561. Its risk depends on the program actually listening on it. General advice for monitoring & logging services:
IANA registry entries for port 561
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| monitor | 561 | TCP, UDP | - | - |
// source: IANA service name and port number registry
Which program uses port 561, and is it reachable?
Linux
sudo ss -ltnup 'sport = :561' # process listening on 561
sudo lsof -nP -i :561macOS
sudo lsof -nP -i :561
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 561 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 561 netstat -ano | findstr :561
From another machine
nmap -p 561 -sV <host> sudo nmap -sU -p 561 <host> nc -zv <host> 561
Block it in the firewall
sudo ufw deny 561/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 561" -Direction Inbound -LocalPort 561 -Protocol TCP -Action Block # Windows
What is port 561 used for?
Port 561 is assigned by IANA to monitor ().
Is port 561 TCP or UDP?
Port 561 is registered for TCP and UDP.
Is it safe to open port 561?
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. Restrict management and monitoring protocols to the monitoring network.
How do I check if port 561 is open?
On Linux run "ss -ltnup 'sport = :561'", on macOS "lsof -nP -i :561", and on Windows "netstat -ano | findstr :561" to see the local process. From another machine, "nmap -p 561 <host>" shows whether it is reachable.
Other monitoring & logging ports
:161 SNMP udp · tcp · high risk :162 SNMP trap udp · tcp · moderate risk :9090 Prometheus / admin consoles tcp · udp · high risk :514 Syslog udp · tcp · moderate risk :6514 Syslog over TLS tcp · udp · dccp · low risk :5601 Kibana tcp · udp · high risk :391 SynOptics SNMP Relay Port tcp · udp :412 Trap Convention Port tcp · udp