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Port 3506 (apc-3506)

IANA assigns port 3506 to apc-3506: APC 3506.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
apc-3506 TCP APC 3506 American Power Conve -
apc-3506 UDP APC 3506 American Power Conve -

Check what is listening on port 3506

Linux: is anything listening on TCP 3506?
sudo ss -tlnp 'sport = :3506'
Linux: UDP 3506
sudo ss -ulnp 'sport = :3506'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3506
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3506 '
Windows (Command Prompt)
netstat -ano | findstr :3506
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3506 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3506
From Windows
Test-NetConnection HOST -Port 3506
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3506

Block port 3506 in the firewall

ufw
sudo ufw deny 3506/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3506 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3506 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3506' -Direction Inbound -Protocol TCP -LocalPort 3506 -Action Block
ufw
sudo ufw deny 3506/udp
iptables
sudo iptables -A INPUT -p udp --dport 3506 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3506 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3506' -Direction Inbound -Protocol UDP -LocalPort 3506 -Action Block

Related ports

3504ironstorm3505ccmcomm3507nesh-broker3508interactionweb

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