Manage farm-level crawl settings in SharePoint Server
APPLIES TO: 
2013 2016 2019 Subscription Edition 
SharePoint in Microsoft 365
You can perform the following procedures to configure certain crawl settings at the farm level:
Configure time-out values for crawler connections in SharePoint Server
Change how long the SharePoint Server search crawler will wait for a connection to a content repository or for a response to a connection attempt.
Configure the crawler in case of SSL certificate warnings in SharePoint Server
Specify whether a SharePoint Server crawler will crawl a site if there is a problem with the site's Secure Sockets Layer (SSL) certificate.
Configure proxy server settings for Search in SharePoint Server
Specify a proxy server to send requests to crawl content or to query federated content repositories.