TCP, or transmission control protocol, is one of the fundamental aspects of secure information transfer over the Internet. As the fourth layer in the OSI model, the TCP protocol ensures that all data sent from one IP address is actually received by another IP address. If a packet did not reach the recipient's IP, TCP would require the packet to be resent, until receipt was confirmed. It is for these reasons that TCP grants the user the ability to provide flow-based data transfer reliably. Secure Socket Shell (SSH) is a UNX-based protocol that allows users to securely log in to a remote computer. SSH ensures that commands between computers are encrypted and secure through several factors, including: (1) both ends of the client/server connection are authenticated using a digital certificate, and (2) passwords are protected by additional encryption. SSH is typically used when accessing a remote computer and executing commands as securely as possible. There are several ways to use SSH, one of which is a manually generated public-private key pair to perform the certification process. Published in 1988, RIPv1 (Routing Information Protocol) uses something known as class routing and a router hop count as the routing metric. Because there is no method to authenticate route updates, the RIPv1 protocol sends copies of routes to its neighbors every 30 seconds. RIPv1 will load/balance traffic in cases where there are multiple paths with the same load to a destination. It also sends triggered updates when a route's metrics have changed, allowing the network to converge faster, rather than waiting for periodic updates. RIPv1 displays information such as: IP address, gateway, interface, metric and/or timer.Portma...... middle of paper ......built-in database to store name and address information for all public hosts on the Internet. DNS also assumes that IP addresses are static, rather than dynamic. ARP, or address resolution protocol, is used to map an IP address to the address of a physical machine (e.g. Ethernet) that has been recognized in the local network. A table, called the ARP cache, maintains a correlation between each MAC address and its corresponding IP address within the network. ARP is responsible for making this correlation and providing address translations in both directions. For example, a host that wishes to obtain a physical address will do so by broadcasting an ARP request over the TCP/IP network. The host on the network that owns the IP address indicated in the request will then respond with its physical hardware address. We can see an example of the initial capture transmission #67.