For advanced authentication options, see: Authentication
LabKey Server uses form-based authentication by default for all user-agents (browsers). However, it will correctly accept http basic authentication headers if presented. This can be useful for command line tools that you might use to automate certain tasks.
For instance, to use wget to retrieve a page readable by 'user1' with password 'secret' you could write:
wget <<protectedurl>> --user user1 --password secret