The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 0.5-1.0 mg/kg can be a lethal dosage for adult humans, and 0.1 mg/kg for children.
IPSec is a suite of protocols that provide security services at IP layer of TCP/IP stack i.e. Network Layer in OSI model. As Andy Lemke mentioned, IPSec suite comprises of two protocols to offer security to. 1. AH - Authentication Header Protocol.(Protocol no: 51) 2. ESP - Encapsulation of security payload Protocol.
IPsec modes. IPsec can operate in two modes: transport and tunnel mode. The default mode for Windows Server 2003 is transport mode. In transport mode, IPsec never encrypts the IP header data (information such as the source and destination address), but in tunnel mode the IP header and payload are encrypted.