You have successfully gained access to a linux server and would like to ensure that...

When the NIDS encounters encrypted traffic, the only analysis it can perform is packet level analysis, since the application layer contents are inaccessible. Given that exploits against today's networks are primarily targeted against network services (application layer entities), packet level analysis ends up doing very little to protect our core business assets.

References: http://www.techrepublic.com/article/avoid-these-five-common-ids-implementation-errors/