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// Other services

Port 1677: groupwise

Port 1677 is assigned by IANA to groupwise (groupwise).

1677

How groupwise works

Other services
client:1677groupwiseresponse client:1677groupwiseresponse

The client sends a request to port 1677 and the groupwise 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 1677 dangerous?

We have no specific security note for port 1677. 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 1677

ServicePortTransportDescriptionReferenceUpdated
groupwise 1677 TCP, UDP groupwise - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1677, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1677'      # process listening on 1677
sudo lsof -nP -i :1677

macOS

sudo lsof -nP -i :1677

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1677 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1677
netstat -ano | findstr :1677

From another machine

nmap -p 1677 -sV <host>
sudo nmap -sU -p 1677 <host>
nc -zv <host> 1677

Block it in the firewall

sudo ufw deny 1677/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1677" -Direction Inbound -LocalPort 1677 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1677 used for?

Port 1677 is assigned by IANA to groupwise (groupwise).

Is port 1677 TCP or UDP?

Port 1677 is registered for TCP and UDP.

Is it safe to open port 1677?

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 1677 is open?

On Linux run "ss -ltnup 'sport = :1677'", on macOS "lsof -nP -i :1677", and on Windows "netstat -ano | findstr :1677" to see the local process. From another machine, "nmap -p 1677 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

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