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Port 4740 (ipfixs)

IANA assigns port 4740 to ipfixs: ipfix protocol over TLS.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ipfixs TCP ipfix protocol over TLS Nevil Brownlee -
ipfixs UDP ipfix protocol over DTLS Nevil Brownlee -
ipfixs SCTP ipfix protocol over DTLS Nevil Brownlee -

Registry dates for this port: registered 2006-10.

Check what is listening on port 4740

Linux: is anything listening on TCP 4740?
sudo ss -tlnp 'sport = :4740'
Linux: UDP 4740
sudo ss -ulnp 'sport = :4740'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4740
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4740 '
Windows (Command Prompt)
netstat -ano | findstr :4740
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4740 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4740
From Windows
Test-NetConnection HOST -Port 4740
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4740

Block port 4740 in the firewall

ufw
sudo ufw deny 4740/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4740 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4740 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4740' -Direction Inbound -Protocol TCP -LocalPort 4740 -Action Block
ufw
sudo ufw deny 4740/udp
iptables
sudo iptables -A INPUT -p udp --dport 4740 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4740 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4740' -Direction Inbound -Protocol UDP -LocalPort 4740 -Action Block

Related ports

4738solera-lpn4739ipfix4741lumimgrd4742sicct, sicct-sdp

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.