HTTPfy

Port 4139 (thrtx)

IANA assigns port 4139 to thrtx: Imperfect Networks Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
thrtx TCP Imperfect Networks Server Dinkar Chivaluri 2 -
thrtx UDP Imperfect Networks Server Dinkar Chivaluri 2 -

Registry dates for this port: registered 2006-02.

Check what is listening on port 4139

Linux: is anything listening on TCP 4139?
sudo ss -tlnp 'sport = :4139'
Linux: UDP 4139
sudo ss -ulnp 'sport = :4139'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4139
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4139 '
Windows (Command Prompt)
netstat -ano | findstr :4139
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4139 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4139
From Windows
Test-NetConnection HOST -Port 4139
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4139

Block port 4139 in the firewall

ufw
sudo ufw deny 4139/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4139 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4139 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4139' -Direction Inbound -Protocol TCP -LocalPort 4139 -Action Block
ufw
sudo ufw deny 4139/udp
iptables
sudo iptables -A INPUT -p udp --dport 4139 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4139 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4139' -Direction Inbound -Protocol UDP -LocalPort 4139 -Action Block

Related ports

4137cl-db-remote4138nettest4140cedros-fds, cedros_fds4141oirtgsvc

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