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Port 186 (kis)

IANA assigns port 186 to kis: KIS Protocol.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
kis TCP KIS Protocol Ralph Droms -
kis UDP KIS Protocol Ralph Droms -

Check what is listening on port 186

Linux: is anything listening on TCP 186?
sudo ss -tlnp 'sport = :186'
Linux: UDP 186
sudo ss -ulnp 'sport = :186'
Linux / macOS: which process owns the port
sudo lsof -nP -i :186
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':186 '
Windows (Command Prompt)
netstat -ano | findstr :186
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 186 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 186
From Windows
Test-NetConnection HOST -Port 186
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 186

Block port 186 in the firewall

ufw
sudo ufw deny 186/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 186 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 186 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 186' -Direction Inbound -Protocol TCP -LocalPort 186 -Action Block
ufw
sudo ufw deny 186/udp
iptables
sudo iptables -A INPUT -p udp --dport 186 -j DROP
nftables
sudo nft add rule inet filter input udp dport 186 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 186' -Direction Inbound -Protocol UDP -LocalPort 186 -Action Block

Related ports

184ocserver185remote-kis187aci188mumps

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