What ports does Honkai Star Rail use, and should I forward them to fix error code 1001_3?

While the exact ports Honkai Star Rail uses aren't publicly documented, you can try forwarding common gaming ports (UDP 3074, 27000-27030, TCP 27015, 27036) in your router settings. However, this is an advanced step and should only be done if you're comfortable with router configuration. Incorrect port forwarding can create security vulnerabilities. Usually, port forwarding isn't required.