Port 5568 (sdt)

IANA assigns port 5568 to sdt: Session Data Transport Multicast.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

sdt TCP Session Data Transport Multicast Daniel W Antonuk -

sdt UDP Session Data Transport Multicast Daniel W Antonuk -

Registry dates for this port: registered 2006-05.

Linux: is anything listening on TCP 5568?

sudo ss -tlnp 'sport = :5568'

Linux: UDP 5568

sudo ss -ulnp 'sport = :5568'

Linux / macOS: which process owns the port

sudo lsof -nP -i :5568

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':5568 '

Windows (Command Prompt)

netstat -ano | findstr :5568

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5568 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 5568

From Windows

Test-NetConnection HOST -Port 5568

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 5568

ufw

sudo ufw deny 5568/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 5568 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 5568 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 5568' -Direction Inbound -Protocol TCP -LocalPort 5568 -Action Block

ufw

sudo ufw deny 5568/udp

iptables

sudo iptables -A INPUT -p udp --dport 5568 -j DROP

nftables

sudo nft add rule inet filter input udp dport 5568 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 5568' -Direction Inbound -Protocol UDP -LocalPort 5568 -Action Block

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