HTTPfy

Port 4742 (sicct, sicct-sdp)

IANA assigns port 4742 to sicct, sicct-sdp: SICCT.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
sicct TCP SICCT - -
sicct-sdp UDP SICCT Service Discovery Protocol TeleTrusT Deutschlan -

Registry dates for this port: registered 2006-04.

Check what is listening on port 4742

Linux: is anything listening on TCP 4742?
sudo ss -tlnp 'sport = :4742'
Linux: UDP 4742
sudo ss -ulnp 'sport = :4742'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4742
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4742 '
Windows (Command Prompt)
netstat -ano | findstr :4742
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4742 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4742
From Windows
Test-NetConnection HOST -Port 4742
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4742

Block port 4742 in the firewall

ufw
sudo ufw deny 4742/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4742 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4742 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4742' -Direction Inbound -Protocol TCP -LocalPort 4742 -Action Block
ufw
sudo ufw deny 4742/udp
iptables
sudo iptables -A INPUT -p udp --dport 4742 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4742 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4742' -Direction Inbound -Protocol UDP -LocalPort 4742 -Action Block

Related ports

4740ipfixs4741lumimgrd4743openhpid4744ifsp

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