Do port checks before proceeding with installation #13
Description
Why?
Pre-emptive step to reduce support issues. The backend usually have no problem churning out the 1-liner Powershell command for client-side to install.
Unfortunately, there are cases where either the first IP address that installation uses is not the actual address for client to download configuration & upload events, &/or there's some firewall configurations to be added.
When & How
When $SFTPCONFURL is defined, we use the address to check against port 2222 (sftp service) & 8888 (to download the sftpconf.zip).
Proceed only when both port are reachable, otherwise abort & prompt error message-box.