This functionality is missing as of Version: 2.2.5 Build:#520
The easiest way to describe this missing functionality is with an example.
In a confluence wiki if one searches for a hostname for example "appserver28nyc" and some pages on the wiki contain the string "appserver28nyc" in a context like "if the server your using is appserver28nyc then blah blah" whereas other pages on the wiki contain the string "appserver28nyc" in a context of like "make sure not to reboot appserver28nyc.dbpool.servers.domain.com since it will" only the former pages will be returned.
This happens because confluence (like other search engines like google) only searches for whole words, not substrings of words. Most search engines (like google) consider the period character "." to define a break in search tokens so that from an indexing perspective "appserver28nyc.dbpool.servers.domain.com" would be considered as 5 seperate tokens appserver28nyc, dbpool, servers, domain, and com. Confluence does not.
An easy way to see this work in other search engines is by searching for "192.168" on any major search engine.
If you create a page in confluence with the string "192.168.1.1" and then search for "192.168" you'll get 0 results.
This would be very useful and would move confluence towards conforming to standard practices in search.