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Port 430 (utmpsd)

IANA assigns port 430 to utmpsd: UTMPSD.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
utmpsd TCP UTMPSD - -
utmpsd UDP UTMPSD - -

Check what is listening on port 430

Linux: is anything listening on TCP 430?
sudo ss -tlnp 'sport = :430'
Linux: UDP 430
sudo ss -ulnp 'sport = :430'
Linux / macOS: which process owns the port
sudo lsof -nP -i :430
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':430 '
Windows (Command Prompt)
netstat -ano | findstr :430
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 430 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 430
From Windows
Test-NetConnection HOST -Port 430
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 430

Block port 430 in the firewall

ufw
sudo ufw deny 430/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 430 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 430 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 430' -Direction Inbound -Protocol TCP -LocalPort 430 -Action Block
ufw
sudo ufw deny 430/udp
iptables
sudo iptables -A INPUT -p udp --dport 430 -j DROP
nftables
sudo nft add rule inet filter input udp dport 430 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 430' -Direction Inbound -Protocol UDP -LocalPort 430 -Action Block

Related ports

428ocs-cmu, ocs_cmu429ocs-amu, ocs_amu431utmpcd432iasd

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