There should be at least two base URLs:
- Base URL for external users
- Base URL for internal users
External users may access JIRA through a firewall and the address of JIRA for external access may be different from the address of the internal server.
Another minor thing is that the base URL is not checked if it contains a '/' at the end.
If you enter a base URL like 'http://www.schniebiwutz.com/jira/' JIRA generates emails with 'http://www.schniebiwutz.com/jira//...'.