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Port 5271 (cuelink, cuelink-disc)

IANA assigns port 5271 to cuelink, cuelink-disc: StageSoft CueLink messaging.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cuelink TCP StageSoft CueLink messaging Todd Pichler -
cuelink-disc UDP StageSoft CueLink discovery Todd Pichler -

Registry dates for this port: registered 2010-03-26.

Check what is listening on port 5271

Linux: is anything listening on TCP 5271?
sudo ss -tlnp 'sport = :5271'
Linux: UDP 5271
sudo ss -ulnp 'sport = :5271'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5271
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5271 '
Windows (Command Prompt)
netstat -ano | findstr :5271
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5271 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5271
From Windows
Test-NetConnection HOST -Port 5271
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5271

Block port 5271 in the firewall

ufw
sudo ufw deny 5271/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5271 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5271 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5271' -Direction Inbound -Protocol TCP -LocalPort 5271 -Action Block
ufw
sudo ufw deny 5271/udp
iptables
sudo iptables -A INPUT -p udp --dport 5271 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5271 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5271' -Direction Inbound -Protocol UDP -LocalPort 5271 -Action Block

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