[improvement] don't dispatch to not connected interface

(just discovered your utility, very nice and useful, thanks)

if i use

`dipatch start ip ipnotconnected`

it works, really good because i don't have to change the start command when i have an interface not connected...

but... dispatch still tries to send requests to the ipnotconnected interface

could be useful to check on startup the ips so no more errors while using internet

thanks