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Port 3875 (pnbscada)

IANA assigns port 3875 to pnbscada: PNBSCADA.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
pnbscada TCP PNBSCADA Philip N Bergstress -
pnbscada UDP PNBSCADA Philip N Bergstress -

Check what is listening on port 3875

Linux: is anything listening on TCP 3875?
sudo ss -tlnp 'sport = :3875'
Linux: UDP 3875
sudo ss -ulnp 'sport = :3875'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3875
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3875 '
Windows (Command Prompt)
netstat -ano | findstr :3875
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3875 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3875
From Windows
Test-NetConnection HOST -Port 3875
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3875

Block port 3875 in the firewall

ufw
sudo ufw deny 3875/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3875 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3875 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3875' -Direction Inbound -Protocol TCP -LocalPort 3875 -Action Block
ufw
sudo ufw deny 3875/udp
iptables
sudo iptables -A INPUT -p udp --dport 3875 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3875 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3875' -Direction Inbound -Protocol UDP -LocalPort 3875 -Action Block

Related ports

3873fagordnc3874sixxsconfig3876dl-agent, dl_agent3877xmpcr-interface

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