Adding realm to username

[Dariusz Nowak]

Hello,

I'm looking for guidance how to configure following scenario:
If user came from host XXX (client IP) without specifying realm/domain (so ex. bob instead of bob at mydomain.com) I need to add it to the request. 

I've found many example how to do that in otherway around - so if stripping domain from incoming request.

Can somebody give me some guidance how I can achieve that? 

I've had a quick look on config/Proxy and correct me if I'm wrong but I believe this is what I need to use to configure it? It's  just getting little bit blurry when I'm going to "What Happens" section and it mentioning hints.

I'm using FreeRadius 3.0.4-6 on Centos7. 

Many thanks
Dariusz