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Port 5728 (io-dist-data, io-dist-group)

IANA assigns port 5728 to io-dist-data, io-dist-group: Dist. I/O Comm. Service Data and Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
io-dist-data TCP Dist. I/O Comm. Service Data and Control Harish Kuttan -
io-dist-group UDP Dist. I/O Comm. Service Group Membership Harish Kuttan -

Registry dates for this port: registered 2010-03-22.

Check what is listening on port 5728

Linux: is anything listening on TCP 5728?
sudo ss -tlnp 'sport = :5728'
Linux: UDP 5728
sudo ss -ulnp 'sport = :5728'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5728
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5728 '
Windows (Command Prompt)
netstat -ano | findstr :5728
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5728 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5728
From Windows
Test-NetConnection HOST -Port 5728
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5728

Block port 5728 in the firewall

ufw
sudo ufw deny 5728/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5728 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5728 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5728' -Direction Inbound -Protocol TCP -LocalPort 5728 -Action Block
ufw
sudo ufw deny 5728/udp
iptables
sudo iptables -A INPUT -p udp --dport 5728 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5728 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5728' -Direction Inbound -Protocol UDP -LocalPort 5728 -Action Block

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