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// Network services

Port 1985: Hot Standby Router Protocol

Port 1985 is assigned by IANA to hsrp (Hot Standby Router Protocol).

1985

How hsrp works

Network services
client:1985hsrpresponse client:1985hsrpresponse

The client sends a request to port 1985 and the hsrp 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
Network services
01 Security

Is port 1985 dangerous?

We have no specific security note for port 1985. Its risk depends on the program actually listening on it. General advice for network services services:

  • Answer only the networks that need the service (no open resolvers, relays or reflectors).
  • UDP services can be abused for DDoS amplification: rate-limit or block them at the edge.
  • Disable legacy test services that have no use in production.
02 Registry

IANA registry entries for port 1985

ServicePortTransportDescriptionReferenceUpdated
hsrp 1985 TCP, UDP Hot Standby Router Protocol RFC 2281 -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1985, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1985'      # process listening on 1985
sudo lsof -nP -i :1985

macOS

sudo lsof -nP -i :1985

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1985 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1985
netstat -ano | findstr :1985

From another machine

nmap -p 1985 -sV <host>
sudo nmap -sU -p 1985 <host>
nc -zv <host> 1985

Block it in the firewall

sudo ufw deny 1985/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1985" -Direction Inbound -LocalPort 1985 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1985 used for?

Port 1985 is assigned by IANA to hsrp (Hot Standby Router Protocol).

Is port 1985 TCP or UDP?

Port 1985 is registered for TCP and UDP.

Is it safe to open port 1985?

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. Answer only the networks that need the service (no open resolvers, relays or reflectors).

How do I check if port 1985 is open?

On Linux run "ss -ltnup 'sport = :1985'", on macOS "lsof -nP -i :1985", and on Windows "netstat -ano | findstr :1985" to see the local process. From another machine, "nmap -p 1985 <host>" shows whether it is reachable.

05 Related
:53 DNS tcp · udp · moderate risk :135 MS RPC tcp · udp · high risk :123 NTP udp · tcp · moderate risk :67 DHCP server udp · tcp · moderate risk :111 rpcbind tcp · udp · high risk :9100 Raw printing (JetDirect) tcp · udp · high risk :631 IPP / CUPS tcp · udp · high risk :5353 mDNS udp · tcp · moderate risk

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