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Port 1386 (checksum)

IANA assigns port 1386 to checksum: CheckSum License Manager.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
checksum TCP CheckSum License Manager Andreas Glocker -
checksum UDP CheckSum License Manager Andreas Glocker -

Check what is listening on port 1386

Linux: is anything listening on TCP 1386?
sudo ss -tlnp 'sport = :1386'
Linux: UDP 1386
sudo ss -ulnp 'sport = :1386'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1386
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1386 '
Windows (Command Prompt)
netstat -ano | findstr :1386
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1386 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1386
From Windows
Test-NetConnection HOST -Port 1386
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1386

Block port 1386 in the firewall

ufw
sudo ufw deny 1386/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1386 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1386 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1386' -Direction Inbound -Protocol TCP -LocalPort 1386 -Action Block
ufw
sudo ufw deny 1386/udp
iptables
sudo iptables -A INPUT -p udp --dport 1386 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1386 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1386' -Direction Inbound -Protocol UDP -LocalPort 1386 -Action Block

Related ports

1384os-licman1385atex-elmd, atex_elmd1387cadsi-lm1388objective-dbc

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