Abstract: A Sniffer is a program on the network traffic by grabbing information travelling over a network [1]. Many people assume computers connected to a switch are safe from sniffing here we go for Antisniffing [2]. Nothing could be further from the truth. Computers connected to switches are just from vulnerable to sniffing. Computers connected to switches are just as vulnerable to sniffing as those connected to a hub. Here in this paper we propose Mobile Agents to detect sniffers. Mobile agents perform a task by migrating and executing on several nodes connected to the network. Ignored to detect sniffers [3], the network administrator sends some special types of mobile agents in the network and collects information from different nodes. After analyzing this information the network administrator can identify the computer system running in promiscuous mode.