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AfsanehRostami
AfsanehRostami
New Member
February 18, 2026
Question

High latency in IPsec dialup tunnel

  • February 18, 2026
  • 2 replies
  • 180 views

Hi everyone

 

I’m experiencing very high latency when FortiClient connects to EMS Cloud over a dial-up IPsec tunnel. The latency is noticeable even with basic tests, for both internal and external traffic.

So far, I have disabled UTM/inspection on the related firewall policies and verified MTU settings on both EMS and the FortiGate. EMS is using the default MTU (1280), and there are no custom MTU settings configured on the FortiGate.

 

2 replies

Stephen_G
Moderator
Stephen_G
Moderator
February 23, 2026

Hello,

 

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible. 

 

If anybody else has any info or advice, please feel free to contribute!

Regards,
Stephen_G - Fortinet Community Team
AEK
SuperUser
AEK
SuperUser
February 24, 2026

Hi Afsaneh

Which FortiGate model, FortiOS version, and FortiClient version.

Besides, did you try disable NPU offload? Does it change anything?

config vpn ipsec phase1-interface
 edit phase-1-name
  set npu-offload disable
end
AEK
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