Port 23400 (novar-dbase)

IANA assigns port 23400 to novar-dbase: Novar Data.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

novar-dbase TCP Novar Data Keith Kilroy -

novar-dbase UDP Novar Data Keith Kilroy -

Registry dates for this port: registered 2006-02.

Linux: is anything listening on TCP 23400?

sudo ss -tlnp 'sport = :23400'

Linux: UDP 23400

sudo ss -ulnp 'sport = :23400'

Linux / macOS: which process owns the port

sudo lsof -nP -i :23400

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':23400 '

Windows (Command Prompt)

netstat -ano | findstr :23400

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 23400 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 23400

From Windows

Test-NetConnection HOST -Port 23400

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

nc -vzu -w 5 HOST 23400

ufw

sudo ufw deny 23400/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 23400 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 23400 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 23400' -Direction Inbound -Protocol TCP -LocalPort 23400 -Action Block

ufw

sudo ufw deny 23400/udp

iptables

sudo iptables -A INPUT -p udp --dport 23400 -j DROP

nftables

sudo nft add rule inet filter input udp dport 23400 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 23400' -Direction Inbound -Protocol UDP -LocalPort 23400 -Action Block

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