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// Other services

Port 5755: OpenMail Desk Gateway server

Port 5755 is assigned by IANA to openmailg (OpenMail Desk Gateway server).

5755

How openmailg works

Other services
client:5755openmailgresponse client:5755openmailgresponse

The client sends a request to port 5755 and the openmailg 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 5755 dangerous?

We have no specific security note for port 5755. 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 5755

ServicePortTransportDescriptionReferenceUpdated
openmailg 5755 TCP, UDP OpenMail Desk Gateway server - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 5755, and is it reachable?

Linux

sudo ss -ltnup 'sport = :5755'      # process listening on 5755
sudo lsof -nP -i :5755

macOS

sudo lsof -nP -i :5755

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5755 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 5755
netstat -ano | findstr :5755

From another machine

nmap -p 5755 -sV <host>
sudo nmap -sU -p 5755 <host>
nc -zv <host> 5755

Block it in the firewall

sudo ufw deny 5755/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 5755" -Direction Inbound -LocalPort 5755 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 5755 used for?

Port 5755 is assigned by IANA to openmailg (OpenMail Desk Gateway server).

Is port 5755 TCP or UDP?

Port 5755 is registered for TCP and UDP.

Is it safe to open port 5755?

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 5755 is open?

On Linux run "ss -ltnup 'sport = :5755'", on macOS "lsof -nP -i :5755", and on Windows "netstat -ano | findstr :5755" to see the local process. From another machine, "nmap -p 5755 <host>" shows whether it is reachable.

05 Related
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