Almost all organizations face an increasing threat to their networks and services they provide.Intrusion detection system (IDS) to take increased beating for failing to meet the expectations of researchers and vendors continue raise.Promises IDS is IDS capable of reliably identifying malicious activity in a large network are premature and never tuned into reality. While virus scanners and firewalls have real benefits and remain virtually unnoticed during normal operation, the situation is different with intrusion detection IDS sensors.State-of-the-art produce hundreds or even thousands of alerts every day.Unfortunately, almost all signs are false positives, ie, they are not related to security relevant incidents. Intrusion Detection and Correlation: Challenges and Solutions analysis of the challenges in interpreting and combining (ie, air) alerts generated by the addition systems.In, academic and commercial systems that exist, classified, their advantages and disadvantages are presented, especially in terms of deployment in large numbers , the site of the real world.