The check command can be used to determine whether the target system is vulnerable to the active exploit module. This is a quick way to verify that all options have been correctly set and that the target is actually vulnerable to exploitation. Not all exploit modules have implemented the check functionality. In many cases it is nearly impossible to determine whether a service is vulnerable without actually exploiting it. A check command should never result in the target system crashing or becoming unavailable. Many modules simply display version information and expect you to analyze it before proceeding.