By comparison, a signature is a stylized script associated with a person. In commerce and the law, a signature on a document is an indication that the person adopts the intentions recorded in the document. Both are comparable to a seal. In many instances, common with engineering companies for example, digital seals are also required for another layer of validation and security.
Network Address Translation (NAT) is a way to map an entire network (or networks) to a single IP address. NAT is necessary when the number of IP addresses assigned to you by your Internet Service Provider is less than the total number of computers that you wish to provide internet access for. NAT is described in RFC 1631. NAT allows you to take advantage of the reserved address blocks described in RFC 1918.
Network Address Translation (NAT) is an IETF standard that enables a local area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. All necessary IP address translations occur where the LAN interfaces with the broader Internet. NAT converts the packet headers (and in some cases the port numbers in the headers) for incoming and outgoing traffic and keeps track of each session.