Search Engine Indexing
There are two settings in your Moodle related to search engine indexing of the site. These can be found under:
The first setting is Open to Google
opentogoogle which determines if google can enter your site as a guest and allow people who find your site to be logged in as guest. This only applies to content that is already open to guest users. This is always disabled by default.
Just be aware that if you do enable this and you have log guest users enabled you may fill up your moodle logs pretty quickly if you have a lot of traffic from search engines.
The second setting available on newer moodle versions is Allow indexing by search engines
allowindexing which allows you to select what level of indexing by search engines is allowed by setting a tag. To disable all indexing use Nowhere.
You can of course also fine tune access using a
robots.txt if required, just be aware that this is not something that is included by default.