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Port 18186 (ohsc)

IANA assigns port 18186 to ohsc: Occupational Health SC.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ohsc TCP Occupational Health SC David Fudge -
ohsc UDP Occupational Health Sc David Fudge -

Registry dates for this port: registered 2003-08.

Check what is listening on port 18186

Linux: is anything listening on TCP 18186?
sudo ss -tlnp 'sport = :18186'
Linux: UDP 18186
sudo ss -ulnp 'sport = :18186'
Linux / macOS: which process owns the port
sudo lsof -nP -i :18186
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':18186 '
Windows (Command Prompt)
netstat -ano | findstr :18186
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 18186 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 18186
From Windows
Test-NetConnection HOST -Port 18186
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 18186

Block port 18186 in the firewall

ufw
sudo ufw deny 18186/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 18186 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 18186 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 18186' -Direction Inbound -Protocol TCP -LocalPort 18186 -Action Block
ufw
sudo ufw deny 18186/udp
iptables
sudo iptables -A INPUT -p udp --dport 18186 -j DROP
nftables
sudo nft add rule inet filter input udp dport 18186 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 18186' -Direction Inbound -Protocol UDP -LocalPort 18186 -Action Block

Related ports

18184opsec-lea18185opsec-omi18187opsec-ela18241checkpoint-rtm

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