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Port 3920 (exasoftport1)

IANA assigns port 3920 to exasoftport1: Exasoft IP Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
exasoftport1 TCP Exasoft IP Port Alan Malik -
exasoftport1 UDP Exasoft IP Port Alan Malik -

Registry dates for this port: registered 2003-11.

Check what is listening on port 3920

Linux: is anything listening on TCP 3920?
sudo ss -tlnp 'sport = :3920'
Linux: UDP 3920
sudo ss -ulnp 'sport = :3920'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3920
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3920 '
Windows (Command Prompt)
netstat -ano | findstr :3920
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3920 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3920
From Windows
Test-NetConnection HOST -Port 3920
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3920

Block port 3920 in the firewall

ufw
sudo ufw deny 3920/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3920 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3920 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3920' -Direction Inbound -Protocol TCP -LocalPort 3920 -Action Block
ufw
sudo ufw deny 3920/udp
iptables
sudo iptables -A INPUT -p udp --dport 3920 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3920 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3920' -Direction Inbound -Protocol UDP -LocalPort 3920 -Action Block

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