Firewalls local connections

Question

I have question about blocking local connections by desktop firewalls. Is there any trend where firewalls block local connections by default or rather they allow local connections.

I want to make app that communicate with second app on the same machine. And i do not want problems with config firewalls (Windows firewall including)

Answer 1

As long you use only 127.0.0.1 (both LISTEN and CONNECT), no Firewall should be a problem.

If there is a FW software dump enough to bother the user to ask permission for 127.0.0.0/8, he/she will be trained to klick "OK" anyways.