Slow download speed in some cases

[Mouftik]

Hello all,

I have been testing my pfSense installation for now 2-3 month and everything was working fine since I noticed this issue.

My problem : I have an optical access to the internet (approximately 250MB/s) and when I try to download an update from the Apple Store I get maximum 200KB/s. And when I try to directly connect my computer to the Provider router, I get 50MB/s.
For info, my network is simple as : Provider Router <-> pfSense <-> computer

If I try Provider Router <-> computer, I get 50MB/s so that's fine.

I had an issue with downloading updates for application through iTunes Store, where I get max 100-200KB/s and configuring pfSense with DNS Forwarder instead of DNS Responder solved the issue (As far as I know, DNS Resolver only do sequential research).
I don't think that it's an hardware issue, because when testing I get a solid 250MB/s for hours without any problem. So is there anything I forgot in my configuration or something else ?