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Port 3902 (nimaux)

IANA assigns port 3902 to nimaux: NIMsh Auxiliary Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
nimaux TCP NIMsh Auxiliary Port Paul B Finley -
nimaux UDP NIMsh Auxiliary Port Paul B Finley -

Registry dates for this port: registered 2003-10.

Check what is listening on port 3902

Linux: is anything listening on TCP 3902?
sudo ss -tlnp 'sport = :3902'
Linux: UDP 3902
sudo ss -ulnp 'sport = :3902'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3902
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3902 '
Windows (Command Prompt)
netstat -ano | findstr :3902
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3902 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3902
From Windows
Test-NetConnection HOST -Port 3902
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3902

Block port 3902 in the firewall

ufw
sudo ufw deny 3902/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3902 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3902 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3902' -Direction Inbound -Protocol TCP -LocalPort 3902 -Action Block
ufw
sudo ufw deny 3902/udp
iptables
sudo iptables -A INPUT -p udp --dport 3902 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3902 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3902' -Direction Inbound -Protocol UDP -LocalPort 3902 -Action Block

Related ports

3900udt-os, udt_os3901nimsh3903charsetmgr3904omnilink-port

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