The article you included provides a list of IPs that need to be whitelisted if your server policy does not allow outbound communications to any IPs/sites. Whilelisting them ensures that your users will not encounter any issues reaching your Okta org.
When a user accesses an application from the Okta side (or via SP-initiated login flow if that's supported by the app), their request will contain both the local user's IP as well as one of the IPs in the same list you provided.
So for both inbound and outbound traffic, the IP list for Okta should be the same.
Technical Support Engineer
Okta Global Customer Care