Port 4063 (ice-router)

IANA assigns port 4063 to ice-router: Ice Firewall Traversal Service (TCP).

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

ice-router TCP Ice Firewall Traversal Service (TCP) - -

ice-router UDP Ice Firewall Traversal Service (TCP) - -

Linux: is anything listening on TCP 4063?

sudo ss -tlnp 'sport = :4063'

Linux: UDP 4063

sudo ss -ulnp 'sport = :4063'

Linux / macOS: which process owns the port

sudo lsof -nP -i :4063

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':4063 '

Windows (Command Prompt)

netstat -ano | findstr :4063

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4063 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 4063

From Windows

Test-NetConnection HOST -Port 4063

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

nc -vzu -w 5 HOST 4063

ufw

sudo ufw deny 4063/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 4063 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 4063 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 4063' -Direction Inbound -Protocol TCP -LocalPort 4063 -Action Block

ufw

sudo ufw deny 4063/udp

iptables

sudo iptables -A INPUT -p udp --dport 4063 -j DROP

nftables

sudo nft add rule inet filter input udp dport 4063 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 4063' -Direction Inbound -Protocol UDP -LocalPort 4063 -Action Block

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