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Umesh
Umesh
Explorer II
November 28, 2025
Question

Synology NAS device with Fortigate DNAT issue

  • November 28, 2025
  • 1 reply
  • 417 views

Dear All,

 

I need support for you all whether issue it at Firewall or with Synology NAS device.

 

 

Synology NAS device is installed our LAN for that I have created DNAT with Synology IP so that external user (over the internet) can download the file. but users are getting very slow speed while downloading the file.

 

I have also created at firewall with no security profile with no IPS, anti, application control, file filter at Firewall level only simple policy with port.

 

Tested with One user which is using local LAN and his bandwidth is also fine and getting up 100 mbps speed.

 

Can anyone tell me where Issue can be . why users are getting very low speed.

 

 

thank you for your support.

 

 

 

 

1 reply

ezhupa
Staff
ezhupa
Staff
November 28, 2025

Hello,

 

Does the connection fail at any particular time?
Do you also experience other issues at the same time, or only the download has performance issues?
IF you do an iperf from the server towards the internet, do you experience any particular issues with performance?
Could also be a limitation on the server side, or a resource issue and not necessarily on the FGT.

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