Network hijacker and sniffer when notebook running

Just run:

```
pyenv local 3.7.0
virtualenv venv
. ./venv/bin/activate
pip install "ipython[notebook]"
jupyter notebook
```

And internet network was unavailable.



Reproduce the report using the listed pyenv, virtualenv, pip install, and jupyter notebook commands, then inspect the attached logs and browser screenshot. Trace what changes when the notebook starts and document the cause; the issue is resolved when starting Jupyter no longer makes the internet unavailable.

Written by the indexing model from the issue text.