Database Software

Friends,

DB: 12c

Host: Linux

I'm investigation options for network data security and looking into options of configuring network data encryption via sqlnet.ora file.

This is new area for me so have some questions

1. Is it good practice to update sqlnet.ora file on both client and server or just updating on server side is sufficient?
2. How to select what kind of algorithm to use or appropriate?
3. Will it also secure data across dblinks or both db needs to have sqlnet.ora to be updated?
4. How can we verify that network encryption was applied?

Any link/blog/metalink reference? I'm only going through official manual currently.

Thanks in advance.