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Port 5081 (sdl-ets)

IANA assigns port 5081 to sdl-ets: SDL - Ent Trans Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
sdl-ets TCP SDL - Ent Trans Server Marc Morin -
sdl-ets UDP SDL - Ent Trans Server Marc Morin -

Registry dates for this port: registered 2002-04.

Check what is listening on port 5081

Linux: is anything listening on TCP 5081?
sudo ss -tlnp 'sport = :5081'
Linux: UDP 5081
sudo ss -ulnp 'sport = :5081'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5081
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5081 '
Windows (Command Prompt)
netstat -ano | findstr :5081
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5081 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5081
From Windows
Test-NetConnection HOST -Port 5081
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5081

Block port 5081 in the firewall

ufw
sudo ufw deny 5081/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5081 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5081 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5081' -Direction Inbound -Protocol TCP -LocalPort 5081 -Action Block
ufw
sudo ufw deny 5081/udp
iptables
sudo iptables -A INPUT -p udp --dport 5081 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5081 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5081' -Direction Inbound -Protocol UDP -LocalPort 5081 -Action Block

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