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Port 4046 (acp-proto)

IANA assigns port 4046 to acp-proto: Accounting Protocol.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
acp-proto TCP Accounting Protocol - -
acp-proto UDP Accounting Protocol - -

Check what is listening on port 4046

Linux: is anything listening on TCP 4046?
sudo ss -tlnp 'sport = :4046'
Linux: UDP 4046
sudo ss -ulnp 'sport = :4046'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4046
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4046 '
Windows (Command Prompt)
netstat -ano | findstr :4046
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4046 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4046
From Windows
Test-NetConnection HOST -Port 4046
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4046

Block port 4046 in the firewall

ufw
sudo ufw deny 4046/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4046 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4046 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4046' -Direction Inbound -Protocol TCP -LocalPort 4046 -Action Block
ufw
sudo ufw deny 4046/udp
iptables
sudo iptables -A INPUT -p udp --dport 4046 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4046 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4046' -Direction Inbound -Protocol UDP -LocalPort 4046 -Action Block

Related ports

4044ltp4045npp4047ctp-state4049wafs

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