Android to listen TCP connection Is it possible to put Android to accept outbound connections, ie. act as a server waiting for connections?

If so, is there any hindrance like an embedded Android firewall?

What I have in mind is to make a server-less, direct Android-to-Android (p2p) connection. My suspicion is that a few applications make use of that, eg. Skype when a call is established.
Your question is very unclear


If you want to share files like from android to android then you can use an app called ShareIt
If you want your android act as SAMBA server, there's Samba Fileshare app
If you want to make your own app that uses P2P between 2 android devices, then you've probably came to wrong place, maybe you'd like to check stackoverflow from top left corner