 Mesquite is the attack in which an attacker pretends to be someone else. For example, the attacker could send updated sales figures to Bob and sign the email as Alice. Again, the email will lead to a series of packets of the internet that are received by Bob. Changing the sender's identity with email is relatively simple, although protection mechanisms exist such as the sender policy framework. Technically, it is also relatively easy to change the source address of IP messages. Such attack is called IP spoofing. Internet service providers often try to protect against such attacks by filtering packets with invalid source addresses, a process that is described in BCP-38.