My application is hosted on Intranet for security purpose.
Can I use Sentry / send data to sentry from intranet?
Short answer: If the application has free (or at least to sentry.io) outbound internet access, yes!
A bit longer answer for when there is no internet access from your application host:
If your app has no internet access (having outbound internet access is different from it being accessible from the internet) most if not all SDKs support setting a HTTP proxy you can use to circumvent that.
Or if a HTTP proxy is no viable solution there is also Relay which you can host internally on a server which does have internet access.
Sentry doesn’t not require access to your application from sentry.io, you send events to it, not the other way around.