CyberHunter
// Email

Port 5429: Billing and Accounting System Exchange

Port 5429 is assigned by IANA to base (Billing and Accounting System Exchange).

5429

How base works

Email
your servertheir serverbase youthembase

Mail servers hand messages to each other over port 5429, one hop at a time, until the recipient's server.

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
Email
01 Security

Is port 5429 dangerous?

We have no specific security note for port 5429. Its risk depends on the program actually listening on it. General advice for email services:

  • Require TLS and authenticated submission.
  • Make sure the server is not an open relay.
  • Publish SPF, DKIM and DMARC for the domain.
02 Registry

IANA registry entries for port 5429

ServicePortTransportDescriptionReferenceUpdated
base 5429 TCP, UDP Billing and Accounting System Exchange - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 5429, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5429'      # process listening on 5429
sudo lsof -nP -i :5429

macOS

sudo lsof -nP -i :5429

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5429 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5429
netstat -ano | findstr :5429

From another machine

nmap -p 5429 -sV <host>
sudo nmap -sU -p 5429 <host>
nc -zv <host> 5429

Block it in the firewall

sudo ufw deny 5429/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5429" -Direction Inbound -LocalPort 5429 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 5429 used for?

Port 5429 is assigned by IANA to base (Billing and Accounting System Exchange).

Is port 5429 TCP or UDP?

Port 5429 is registered for TCP and UDP.

Is it safe to open port 5429?

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. Require TLS and authenticated submission.

How do I check if port 5429 is open?

On Linux run "ss -ltnup 'sport = :5429'", on macOS "lsof -nP -i :5429", and on Windows "netstat -ano | findstr :5429" to see the local process. From another machine, "nmap -p 5429 <host>" shows whether it is reachable.

05 Related