HTTPfy

Port 3611 (six-degrees)

IANA assigns port 3611 to six-degrees: Six Degrees Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
six-degrees TCP Six Degrees Port Zach Nies -
six-degrees UDP Six Degrees Port Zach Nies -

Registry dates for this port: registered 2002-09.

Check what is listening on port 3611

Linux: is anything listening on TCP 3611?
sudo ss -tlnp 'sport = :3611'
Linux: UDP 3611
sudo ss -ulnp 'sport = :3611'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3611
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3611 '
Windows (Command Prompt)
netstat -ano | findstr :3611
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3611 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3611
From Windows
Test-NetConnection HOST -Port 3611
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3611

Block port 3611 in the firewall

ufw
sudo ufw deny 3611/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3611 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3611 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3611' -Direction Inbound -Protocol TCP -LocalPort 3611 -Action Block
ufw
sudo ufw deny 3611/udp
iptables
sudo iptables -A INPUT -p udp --dport 3611 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3611 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3611' -Direction Inbound -Protocol UDP -LocalPort 3611 -Action Block

Related ports

3609cpdi-pidas-cm3610echonet3612dataprotector3613alaris-disc

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