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Port 3913 (listcrt-port)

IANA assigns port 3913 to listcrt-port: ListCREATOR Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
listcrt-port TCP ListCREATOR Port Tomokazu Asai -
listcrt-port UDP ListCREATOR Port Tomokazu Asai -

Registry dates for this port: registered 2003-11.

Check what is listening on port 3913

Linux: is anything listening on TCP 3913?
sudo ss -tlnp 'sport = :3913'
Linux: UDP 3913
sudo ss -ulnp 'sport = :3913'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3913
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3913 '
Windows (Command Prompt)
netstat -ano | findstr :3913
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3913 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3913
From Windows
Test-NetConnection HOST -Port 3913
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3913

Block port 3913 in the firewall

ufw
sudo ufw deny 3913/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3913 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3913 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3913' -Direction Inbound -Protocol TCP -LocalPort 3913 -Action Block
ufw
sudo ufw deny 3913/udp
iptables
sudo iptables -A INPUT -p udp --dport 3913 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3913 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3913' -Direction Inbound -Protocol UDP -LocalPort 3913 -Action Block

Related ports

3911prnstatus3912gbmt-stars3914listcrt-port-23915agcat

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