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Port 9401 (sec-t4net-clt)

IANA assigns port 9401 to sec-t4net-clt: Samsung Twain for Network Client.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
sec-t4net-clt TCP Samsung Twain for Network Client Dongkeun Kim -
sec-t4net-clt UDP Samsung Twain for Network Client Dongkeun Kim -

Registry dates for this port: registered 2007-02.

Check what is listening on port 9401

Linux: is anything listening on TCP 9401?
sudo ss -tlnp 'sport = :9401'
Linux: UDP 9401
sudo ss -ulnp 'sport = :9401'
Linux / macOS: which process owns the port
sudo lsof -nP -i :9401
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':9401 '
Windows (Command Prompt)
netstat -ano | findstr :9401
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 9401 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 9401
From Windows
Test-NetConnection HOST -Port 9401
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 9401

Block port 9401 in the firewall

ufw
sudo ufw deny 9401/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 9401 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 9401 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 9401' -Direction Inbound -Protocol TCP -LocalPort 9401 -Action Block
ufw
sudo ufw deny 9401/udp
iptables
sudo iptables -A INPUT -p udp --dport 9401 -j DROP
nftables
sudo nft add rule inet filter input udp dport 9401 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 9401' -Direction Inbound -Protocol UDP -LocalPort 9401 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.