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Port 3347 (phoenix-rpc)

IANA assigns port 3347 to phoenix-rpc: Phoenix RPC.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
phoenix-rpc TCP Phoenix RPC Ian Anderson -
phoenix-rpc UDP Phoenix RPC Ian Anderson -

Check what is listening on port 3347

Linux: is anything listening on TCP 3347?
sudo ss -tlnp 'sport = :3347'
Linux: UDP 3347
sudo ss -ulnp 'sport = :3347'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3347
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3347 '
Windows (Command Prompt)
netstat -ano | findstr :3347
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3347 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3347
From Windows
Test-NetConnection HOST -Port 3347
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3347

Block port 3347 in the firewall

ufw
sudo ufw deny 3347/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3347 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3347 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3347' -Direction Inbound -Protocol TCP -LocalPort 3347 -Action Block
ufw
sudo ufw deny 3347/udp
iptables
sudo iptables -A INPUT -p udp --dport 3347 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3347 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3347' -Direction Inbound -Protocol UDP -LocalPort 3347 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.