- Restrict management and monitoring protocols to the monitoring network.
- Replace community strings and default credentials.
- Send logs over TLS.
Port 3998: Distributed Nagios Executor Service
Port 3998 is assigned by IANA to dnx (Distributed Nagios Executor Service).
3998
How dnx works
Monitoring & loggingThe monitoring server collects metrics, alerts or logs from devices over port 3998.
- 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
- Monitoring & logging
Is port 3998 dangerous?
We have no specific security note for port 3998. Its risk depends on the program actually listening on it. General advice for monitoring & logging services:
IANA registry entries for port 3998
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| dnx | 3998 | TCP, UDP | Distributed Nagios Executor Service | - | 2007-11-06 |
// source: IANA service name and port number registry
Which program uses port 3998, and is it reachable?
Linux
sudo ss -ltnup 'sport = :3998' # process listening on 3998
sudo lsof -nP -i :3998macOS
sudo lsof -nP -i :3998
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3998 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 3998 netstat -ano | findstr :3998
From another machine
nmap -p 3998 -sV <host> sudo nmap -sU -p 3998 <host> nc -zv <host> 3998
Block it in the firewall
sudo ufw deny 3998/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 3998" -Direction Inbound -LocalPort 3998 -Protocol TCP -Action Block # Windows
What is port 3998 used for?
Port 3998 is assigned by IANA to dnx (Distributed Nagios Executor Service).
Is port 3998 TCP or UDP?
Port 3998 is registered for TCP and UDP.
Is it safe to open port 3998?
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 3998 is open?
On Linux run "ss -ltnup 'sport = :3998'", on macOS "lsof -nP -i :3998", and on Windows "netstat -ano | findstr :3998" to see the local process. From another machine, "nmap -p 3998 <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