For content crawling SPS should be using port 80. Here is a paragraph I
copied from a document, maybe it will help.
"SharePoint Portal server 2001 uses the Hypertext Transfer Protocol
(HTTP) verbs, the Distributed Authoring and Versioning (DAV) set of HTTP
extensions, and a custom verb called INVOKE. If you use a proxy server,
it must be configured to pass these verbs."