HTTPfy

Port 3547 (symantec-sim)

IANA assigns port 3547 to symantec-sim: Symantec SIM.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
symantec-sim TCP Symantec SIM George Dzieciol -
symantec-sim UDP Symantec SIM George Dzieciol -

Registry dates for this port: registered 2002-07.

Check what is listening on port 3547

Linux: is anything listening on TCP 3547?
sudo ss -tlnp 'sport = :3547'
Linux: UDP 3547
sudo ss -ulnp 'sport = :3547'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3547
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3547 '
Windows (Command Prompt)
netstat -ano | findstr :3547
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3547 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3547
From Windows
Test-NetConnection HOST -Port 3547
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3547

Block port 3547 in the firewall

ufw
sudo ufw deny 3547/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3547 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3547 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3547' -Direction Inbound -Protocol TCP -LocalPort 3547 -Action Block
ufw
sudo ufw deny 3547/udp
iptables
sudo iptables -A INPUT -p udp --dport 3547 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3547 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3547' -Direction Inbound -Protocol UDP -LocalPort 3547 -Action Block

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