Splunk works fine disconnected from the internet. The default login screen has the browser check back with Splunk for upgrade and update notifications. There is no harm is these fail, and the attempts can be turned off in configuration.
What I mean is "isolated network" ... So it is not temporary ... Always no connection with Splunk homebase ... How could we setup to get everything we need to do without using firefox? Maybe using commands on terminal?
You'll have to download the splunk installation package, any apps, and other stuff you need on another host (that has a connection) and then transfer it to your server via FTP, SCP, USB or whatever means you have at your disposal.