CyberHunter
Local dataset, no network
// Other services

Port 4031: UUCP over SSL

Port 4031 is assigned by IANA to suucp (UUCP over SSL).

4031

How suucp works

Other services
client:4031#%&@!x9response? client:4031#%&@!x9response?

The client sends a request to port 4031 and the suucp service answers. Everything is encrypted: someone on the path only sees unreadable bytes.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
EncryptedTLS or built-in crypto
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 4031 dangerous?

We have no specific security note for port 4031. 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 4031

ServicePortTransportDescriptionReferenceUpdated
suucp 4031 TCP, UDP UUCP over SSL - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 4031, and is it reachable?

Linux

sudo ss -ltnup 'sport = :4031'      # process listening on 4031
sudo lsof -nP -i :4031

macOS

sudo lsof -nP -i :4031

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 4031 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 4031
netstat -ano | findstr :4031

From another machine

nmap -p 4031 -sV <host>
sudo nmap -sU -p 4031 <host>
nc -zv <host> 4031

Block it in the firewall

sudo ufw deny 4031/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 4031" -Direction Inbound -LocalPort 4031 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 4031 used for?

Port 4031 is assigned by IANA to suucp (UUCP over SSL).

Is port 4031 TCP or UDP?

Port 4031 is registered for TCP and UDP.

Is it safe to open port 4031?

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 4031 is open?

On Linux run "ss -ltnup 'sport = :4031'", on macOS "lsof -nP -i :4031", and on Windows "netstat -ano | findstr :4031" to see the local process. From another machine, "nmap -p 4031 <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

Latest vulnerability news

All news