SIP Message Inspection feature helps troubleshoot SIP traffic through Communications Server. It is activated by setting the SMI log domain to level FINE.
Open the Admin Console in a browser.
For the developer profile, go to Application Server -> Logging -> Log Levels. For the cluster profile, go to Configurations -> Configuration -> Logging -> Logging Settings -> Log Levels.
In the Log Levels page, in the Additional Properties section, set the smi proerty to FINE.