Setting up SIP Server and receive and reject calls from another SIP server

[adameffandi]

Hi, I have some questions regarding Routr, Fonoster & SIP in general. I'm quite new to SIP related topics, so I'm sorry if my question is too basic.

I'm planning to setup a SIP gateway/server/proxy to receive an incoming call from another SIP gateway (I believe this is what is called SIP Trunking). Once the call reach my SIP gateway/server/proxy, it needs to run a code to reject the call and then store its call detail recording (CDR).

1. I have confusion on the terms SIP server/gateway/proxy. Does these 3 terms means anything different or the same?
2. I did some research into Routr tried setting it up. In my use case, does Routr acts as SIP server/gateway/proxy?
3. I also saw that in Fonoster has SIP Network menu and it matches some of the menu in Routr dashboard. What is the difference between these two?
4. I saw Fonoster example where we can write codes to accept calls. I'm assuming this can be used to achieve my second goal which is to reject incoming calls & store CDR. I also see that Fonoster has Trunking menu. What is the relationship between Routr & Fonoster? Do I need both to achieve my use case or just need Fonoster?