CyberHunter
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// Other services

Port 3125: A13-AN Interface

Port 3125 is assigned by IANA to a13-an (A13-AN Interface).

3125

How a13-an works

Other services
client:3125a13-anresponse client:3125a13-anresponse

The client sends a request to port 3125 and the a13-an 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 3125 dangerous?

We have no specific security note for port 3125. 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 3125

ServicePortTransportDescriptionReferenceUpdated
a13-an 3125 TCP, UDP A13-AN Interface - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 3125, and is it reachable?

Linux

sudo ss -ltnup 'sport = :3125'      # process listening on 3125
sudo lsof -nP -i :3125

macOS

sudo lsof -nP -i :3125

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 3125 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 3125
netstat -ano | findstr :3125

From another machine

nmap -p 3125 -sV <host>
sudo nmap -sU -p 3125 <host>
nc -zv <host> 3125

Block it in the firewall

sudo ufw deny 3125/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 3125" -Direction Inbound -LocalPort 3125 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 3125 used for?

Port 3125 is assigned by IANA to a13-an (A13-AN Interface).

Is port 3125 TCP or UDP?

Port 3125 is registered for TCP and UDP.

Is it safe to open port 3125?

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 3125 is open?

On Linux run "ss -ltnup 'sport = :3125'", on macOS "lsof -nP -i :3125", and on Windows "netstat -ano | findstr :3125" to see the local process. From another machine, "nmap -p 3125 <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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