Network connection is not required for core functionality of PSoC Creator. The following optional features require network access -
1. Downloadable example projects, device packs, and components (download.cypress.com:80)
2. Start Page content (www.cypress.com:80,www.cypress.com:443)
3. Product registration (secure.cypress.com:443)
4. Feedback/surveys (www.mynpssurvey.com:80)
5. Telemetry (secure.cypress.com:443)
Note that these are subject to change in the future revisions of PSoC Creator.
Please let me know if this worked for you.
Thanks and Regards,
Rakshith M B