The question seems to be quite straight and easy, however I have not been able to find a proper answer. 

In haproxy I have 1 backend, say: 

* backend-1

and 2 frontends, say: 

* frontend-1
* frontend-2

In the backend stanza I want to set a "timeout server" parameter, but, only if the connection comes from frontend-1. 

As I didn't find anything I tried to figure it out myself: 

```
backend backend-1
    bind *:80
    option <blahblah_option>
    timeout server 1d if frontend frontend-1

```

This syntax does not work, and I am mentioning it to let understand what I am trying to achieve.