A method performed in a processor of an intrusion detection/prevention system (IDS/IPS) checks for valid packets in an SMB named pipe in a communication network. In a processor configured as an IDS/IPS, a packet in a transmission is received and a kind of application of a target of the packet is determined. Also, the data in the packet is inspected by the IDS/IPS as part of the SMB named pipe on only one of a condition that: (a) the FID in an SMB command header of the packet is valid (i) for segments/fragments in the SMB named pipe and (ii) for the determined kind of application of the target of the packet, as indicated by a reassembly table, and (b) the determined kind of application of the target of the packet does not check the FID, as indicated by the reassembly table.