So my server administrator found out that few of the Valid URLs on our site are generating 404s. These URLs are generated by XF installed on our site. The server admin has asked following questions to me -
"How the URLs are being generated. What script generates them? What creates the URLs in question? By what process?"
Which valid URLs are on your site that are generating 404s?
Also, why does he need to know the answer to that question?
Whatever you do, do not allow any one to suggest making changes to the XenForo core files. If there's a problem, it should be reported for troubleshooting (which can begin with my opening question) or ultimately a bug report can be filed.
He's a server administrator, so he probably knows his stuff and is trustworthy. I'd imagine he wants to know the answer that so he can continue trying to debug it.. nothing to make a big deal of.
I will agree though that if this is a problem occurring under XF, the community here is probably more knowledgeable and will be able to track down the issue quicker. And if it's not from custom code, a bug report definitely should be filed.
Ok, I guess I figured out the issue on my own. I had redirected our vB+vBSEO installation from /forum/ to Xenforo (/community/) in December last year. Now the specific threads that show 'file not found' in server logs were linking to the attachments which still resided in the /forum/ folder of our server. So basically, the posts have hardcoded URLs that point to the files that do not exist on the server.
I think I'll just leave the things as it is. These aren't the 404 as I had imagined; because Fetching these URLs as Google Bot shows 200 OK message.