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// Other services

Port 18187: OPSEC ELA

Port 18187 is assigned by IANA to opsec-ela (OPSEC ELA).

18187

How opsec-ela works

Other services
client:18187opsec-elaresponse client:18187opsec-elaresponse

The client sends a request to port 18187 and the opsec-ela service answers.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 18187 dangerous?

We have no specific security note for port 18187. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 18187

ServicePortTransportDescriptionReferenceUpdated
opsec-ela 18187 TCP, UDP OPSEC ELA - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 18187, and is it reachable?

Linux

sudo ss -ltnup 'sport = :18187'      # process listening on 18187
sudo lsof -nP -i :18187

macOS

sudo lsof -nP -i :18187

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 18187 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 18187
netstat -ano | findstr :18187

From another machine

nmap -p 18187 -sV <host>
sudo nmap -sU -p 18187 <host>
nc -zv <host> 18187

Block it in the firewall

sudo ufw deny 18187/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 18187" -Direction Inbound -LocalPort 18187 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 18187 used for?

Port 18187 is assigned by IANA to opsec-ela (OPSEC ELA).

Is port 18187 TCP or UDP?

Port 18187 is registered for TCP and UDP.

Is it safe to open port 18187?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 18187 is open?

On Linux run "ss -ltnup 'sport = :18187'", on macOS "lsof -nP -i :18187", and on Windows "netstat -ano | findstr :18187" to see the local process. From another machine, "nmap -p 18187 <host>" shows whether it is reachable.

05 Related
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