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Port 43000 (recvr-rc, recvr-rc-disc)

IANA assigns port 43000 to recvr-rc, recvr-rc-disc: Receiver Remote Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
recvr-rc TCP Receiver Remote Control Research Electronics International -
recvr-rc-disc UDP Receiver Remote Control Discovery Research Electronics International -

Registry dates for this port: registered 2012-12-20.

Check what is listening on port 43000

Linux: is anything listening on TCP 43000?
sudo ss -tlnp 'sport = :43000'
Linux: UDP 43000
sudo ss -ulnp 'sport = :43000'
Linux / macOS: which process owns the port
sudo lsof -nP -i :43000
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':43000 '
Windows (Command Prompt)
netstat -ano | findstr :43000
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 43000 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 43000
From Windows
Test-NetConnection HOST -Port 43000
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 43000

Block port 43000 in the firewall

ufw
sudo ufw deny 43000/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 43000 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 43000 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 43000' -Direction Inbound -Protocol TCP -LocalPort 43000 -Action Block
ufw
sudo ufw deny 43000/udp
iptables
sudo iptables -A INPUT -p udp --dport 43000 -j DROP
nftables
sudo nft add rule inet filter input udp dport 43000 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 43000' -Direction Inbound -Protocol UDP -LocalPort 43000 -Action Block

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