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Port 6671 (p4p-portal)

IANA assigns port 6671 to p4p-portal: P4P Portal Service.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
p4p-portal TCP P4P Portal Service Chris Griffiths -
p4p-portal UDP P4P Portal Service Chris Griffiths -

Registry dates for this port: registered 2008-07-28.

Check what is listening on port 6671

Linux: is anything listening on TCP 6671?
sudo ss -tlnp 'sport = :6671'
Linux: UDP 6671
sudo ss -ulnp 'sport = :6671'
Linux / macOS: which process owns the port
sudo lsof -nP -i :6671
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':6671 '
Windows (Command Prompt)
netstat -ano | findstr :6671
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 6671 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 6671
From Windows
Test-NetConnection HOST -Port 6671
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 6671

Block port 6671 in the firewall

ufw
sudo ufw deny 6671/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 6671 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 6671 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 6671' -Direction Inbound -Protocol TCP -LocalPort 6671 -Action Block
ufw
sudo ufw deny 6671/udp
iptables
sudo iptables -A INPUT -p udp --dport 6671 -j DROP
nftables
sudo nft add rule inet filter input udp dport 6671 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 6671' -Direction Inbound -Protocol UDP -LocalPort 6671 -Action Block

Related ports

6669ircu6670vocaltec-gold6672vision-server, vision_server6673vision-elmd, vision_elmd

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