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// Monitoring & logging

Port 4740: ipfix protocol over TLS

Port 4740 is assigned by IANA to ipfixs (ipfix protocol over TLS).

4740

How ipfixs works

Monitoring & logging
monitoringdeviceipfixs monitoringdeviceipfixs

The monitoring server collects metrics, alerts or logs from devices over port 4740. Everything is encrypted: someone on the path only sees unreadable bytes.

Transport
TCP · UDP · SCTP
Exposure risk
not rated depends on the program listening
Encryption
EncryptedTLS or built-in crypto
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Monitoring & logging
01 Security

Is port 4740 dangerous?

We have no specific security note for port 4740. Its risk depends on the program actually listening on it. General advice for monitoring & logging services:

  • Restrict management and monitoring protocols to the monitoring network.
  • Replace community strings and default credentials.
  • Send logs over TLS.
02 Registry

IANA registry entries for port 4740

ServicePortTransportDescriptionReferenceUpdated
ipfixs 4740 TCP, UDP, SCTP ipfix protocol over TLS - 2006-10

// source: IANA service name and port number registry

03 Check it

Which program uses port 4740, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4740'      # process listening on 4740
sudo lsof -nP -i :4740

macOS

sudo lsof -nP -i :4740

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4740 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4740
netstat -ano | findstr :4740

From another machine

nmap -p 4740 -sV <host>
sudo nmap -sU -p 4740 <host>
nc -zv <host> 4740

Block it in the firewall

sudo ufw deny 4740/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4740" -Direction Inbound -LocalPort 4740 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4740 used for?

Port 4740 is assigned by IANA to ipfixs (ipfix protocol over TLS).

Is port 4740 TCP or UDP?

Port 4740 is registered for TCP and UDP and SCTP.

Is it safe to open port 4740?

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 4740 is open?

On Linux run "ss -ltnup 'sport = :4740'", on macOS "lsof -nP -i :4740", and on Windows "netstat -ano | findstr :4740" to see the local process. From another machine, "nmap -p 4740 <host>" shows whether it is reachable.

05 Related
: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

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