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Port 612 (hmmp-ind)

IANA assigns port 612 to hmmp-ind: HMMP Indication.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
hmmp-ind TCP HMMP Indication - -
hmmp-ind UDP HMMP Indication - -

Check what is listening on port 612

Linux: is anything listening on TCP 612?
sudo ss -tlnp 'sport = :612'
Linux: UDP 612
sudo ss -ulnp 'sport = :612'
Linux / macOS: which process owns the port
sudo lsof -nP -i :612
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':612 '
Windows (Command Prompt)
netstat -ano | findstr :612
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 612 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 612
From Windows
Test-NetConnection HOST -Port 612
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 612

Block port 612 in the firewall

ufw
sudo ufw deny 612/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 612 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 612 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 612' -Direction Inbound -Protocol TCP -LocalPort 612 -Action Block
ufw
sudo ufw deny 612/udp
iptables
sudo iptables -A INPUT -p udp --dport 612 -j DROP
nftables
sudo nft add rule inet filter input udp dport 612 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 612' -Direction Inbound -Protocol UDP -LocalPort 612 -Action Block

Related ports

610npmp-local611npmp-gui613hmmp-op614sshell

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