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Port 3939 (aamp)

IANA assigns port 3939 to aamp: Anti-virus Application Management Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
aamp TCP Anti-virus Application Management Port In sik Choi -
aamp UDP Anti-virus Application Management Port In sik Choi -

Registry dates for this port: registered 2002-02.

Check what is listening on port 3939

Linux: is anything listening on TCP 3939?
sudo ss -tlnp 'sport = :3939'
Linux: UDP 3939
sudo ss -ulnp 'sport = :3939'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3939
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3939 '
Windows (Command Prompt)
netstat -ano | findstr :3939
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3939 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3939
From Windows
Test-NetConnection HOST -Port 3939
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3939

Block port 3939 in the firewall

ufw
sudo ufw deny 3939/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3939 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3939 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3939' -Direction Inbound -Protocol TCP -LocalPort 3939 -Action Block
ufw
sudo ufw deny 3939/udp
iptables
sudo iptables -A INPUT -p udp --dport 3939 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3939 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3939' -Direction Inbound -Protocol UDP -LocalPort 3939 -Action Block

Related ports

3937dvbservdsc3938dbcontrol-agent, dbcontrol_agent3940xecp-node3941homeportal-web

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