What can I do to reduce the time caused by redirection?

This is the waterfall chart of my site:

This is the what my flow looks like:

1. User visits http://mysite
2. User gets redirected to site1 for IP verification
3. If pass, User gets redirected to site2, my tracker
4. User reaches site3 which is my templating engine (flask)

Right now, when I visit the site, the site doesn't display anything until the user reaches site3.

Assuming the step 1, 2, 3 are all external services, what can I do to reduce their time?