Traffic shaping problems with NAT

Temporary forum to discuss issues and problems during a VirtualBox Beta or Release Candidate phase.
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Air Force One
Posts: 154
Joined: 6. Oct 2017, 16:54
Primary OS: MS Windows other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Windows
Location: Germany

Traffic shaping problems with NAT

Post by Air Force One »

I see the following issue: if I download some file, the download starts with the whole speed of the channel, but the speed quickly starts to drop. This happens with any download, I try files here (release, beta, development snapshot), Sourceforge, anything else. One can see this in the session information window, network gadget.

This doesn't happen directly on the host and from 7.0.20 / 21 versions with same VM. The only difference is a new network engine with IPv6 support or IPv6 somehow itself.

Maybe it's a ping trouble. If I run an internet speed test in the VM, the speed drop happens way slower. I can download to the virtual HDD in the VM or to the shared folder - this also doesn't matter for this issue.

My combination is Windows 10 host and Windows 11 guest with latest updates.

Maybe there is a connection with "VirtualBox VM 7.1.0_BETA2 r164448 IPv6 NAT "no route" error" issue?
mikest82
Posts: 6
Joined: 1. May 2012, 02:56

Re: Traffic shaping problems with NAT

Post by mikest82 »

Maybe there is a connection with "VirtualBox VM 7.1.0_BETA2 r164448 IPv6 NAT "no route" error" issue?
It is very possible.
Do have Internet with IPv6?
Try to disable IPv6 in the guest operating system
Air Force One
Posts: 154
Joined: 6. Oct 2017, 16:54
Primary OS: MS Windows other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Windows
Location: Germany

Re: Traffic shaping problems with NAT

Post by Air Force One »

mikest82 wrote: 10. Sep 2024, 18:44 Try to disable IPv6 in the guest operating system
Disabling IPv6 in the guest OS didn't help. Vice versa: now the download already starts at a slow speed and tries to speed up a little, but never achieves the whole speed of the channel. So the problem isn't IPv6, but the whole new network NAT stack.

It looks like probably some buffer is filled initially at full speed and has some problems to fill this buffer afterward, as download continues?
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