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// Other services

Port 1987: cisco RSRB Priority 1 port

Port 1987 is assigned by IANA to tr-rsrb-p1 (cisco RSRB Priority 1 port).

1987

How tr-rsrb-p1 works

Other services
client:1987tr-rsrb-p1response client:1987tr-rsrb-p1response

The client sends a request to port 1987 and the tr-rsrb-p1 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 1987 dangerous?

We have no specific security note for port 1987. 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 1987

ServicePortTransportDescriptionReferenceUpdated
tr-rsrb-p1 1987 TCP, UDP cisco RSRB Priority 1 port - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1987, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1987'      # process listening on 1987
sudo lsof -nP -i :1987

macOS

sudo lsof -nP -i :1987

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1987 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1987
netstat -ano | findstr :1987

From another machine

nmap -p 1987 -sV <host>
sudo nmap -sU -p 1987 <host>
nc -zv <host> 1987

Block it in the firewall

sudo ufw deny 1987/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1987" -Direction Inbound -LocalPort 1987 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1987 used for?

Port 1987 is assigned by IANA to tr-rsrb-p1 (cisco RSRB Priority 1 port).

Is port 1987 TCP or UDP?

Port 1987 is registered for TCP and UDP.

Is it safe to open port 1987?

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 1987 is open?

On Linux run "ss -ltnup 'sport = :1987'", on macOS "lsof -nP -i :1987", and on Windows "netstat -ano | findstr :1987" to see the local process. From another machine, "nmap -p 1987 <host>" shows whether it is reachable.

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