Port 4646 (dots-signal)

IANA assigns port 4646 to dots-signal: Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Protocol. The service name is used to construct the SRV service names "_dots-signal._udp" and "_dots-signal._tcp" for discovering DOTS servers used to establish DOTS signal channel..

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

dots-signal TCP Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Protocol. The service name is used to construct the SRV service names "_dots-signal._udp" and "_dots-signal._tcp" for discovering DOTS servers used to establish DOTS signal channel. IESG RFC 8973, RFC 9132

dots-signal UDP Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Channel Protocol. The service name is used to construct the SRV service names "_dots-signal._udp" and "_dots-signal._tcp" for discovering DOTS servers used to establish DOTS signal channel. IESG RFC 8973, RFC 9132

Registry dates for this port: registered 2020-01-16, last modified 2021-06-14.

Check what is listening on port 4646

Linux: is anything listening on TCP 4646?

sudo ss -tlnp 'sport = :4646'

Linux: UDP 4646

sudo ss -ulnp 'sport = :4646'

Linux / macOS: which process owns the port

sudo lsof -nP -i :4646

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':4646 '

Windows (Command Prompt)

netstat -ano | findstr :4646

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4646 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 4646

From Windows

Test-NetConnection HOST -Port 4646

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

nc -vzu -w 5 HOST 4646

Block port 4646 in the firewall

ufw

sudo ufw deny 4646/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 4646 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 4646 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 4646' -Direction Inbound -Protocol TCP -LocalPort 4646 -Action Block

ufw

sudo ufw deny 4646/udp