Performance drops when enabling OpenVPN and IDS/IPS simultaneously on OPNsense

[willsmith]

Hi everyone,

I am running OPNsense on x86_64 hardware (i5, 8GB RAM). When OpenVPN site-to-site and IDS/IPS (Suricata inline) are enabled at the same time, the network performance drops quite significantly:

VPN throughput drops about 20–30% compared to when IDS/IPS is disabled.

CPU load increases sharply during peak hours.

I have tried:

Enable AES-NI and hardware offloading.
Reduce Suricata rule set.

But the situation has not improved much.

Question:

Is there any way to optimize the configuration to reduce the impact between VPN and IDS/IPS?
Does upgrading hardware (CPU/RAM) really solve this problem?

Looking forward to receiving comments from those with experience.
Thanks!

[Patrick M. Hausen]

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