Return to top level domain with url_for()

Question

I have a page on http://127.0.0.1:5000/, which redirects to http://127.0.0.1:5000/results

in my /results page, I want to include a link that will return me to http://127.0.0.1:5000/. I've tried various things using url_for():

<h2>Or search <a href="{{ url_for(filename='/') }}">something else</a></h2>
<h2>Or search <a href="{{ url_for('static', filename='/') }}">something else</a></h2>

However these throw errors such as TypeError: url_for() missing 1 required positional argument: 'endpoint'

(keep in mind I can't just do href="http://127.0.0.1:5000" because the url might change, and I don't want to have to change it manually

How can I do that? (sorry for noob question)