Very slow response from proxy

Hi all,

I’m using the following container for setting up proxy to be able to track network traffic while selenium tests’ execution.

There are no issues accessing proxy container. But response time is drastically slow.

Here’s a video recorded inside container without proxy usage:

And this one uses proxy:

Note that proxy works much faster, when it’s used outside containers.
Any idea if it’s a Docker issue or I just need to tune containers’ configuration somehow?

Regards,
Sergey