The Secure Socket Shell (SSH)

TCP, or transmission control protocol, is one of the most fundamental aspects of guaranteed information transfer on the Internet. As the fourth layer in the OSI model, the TCP protocol ensures that all data sent from one IP address is, in fact, received by another IP address. If a packet did not make it the recipient IP, TCP would call for the packet to be sent again, until confirmation of reception. It is due to these reasons that TCP grants the user the capability of providing stream based transfer of data reliably. The Secure Socket Shell (SSH) is a UNX-based protocol allowing users to securely gain access to a remote computer. SSH ensures that commands between computers are encrypted and secure due to a several things, including: (1) Both ends of the client/server connection are authenticated using a digital certification, and (2) passwords are protected by further encryption. SSH is typically used when logging into a remote machine and executing commands as securely as possible. There are several ways of using SSH, one being a manually generated public-private key pair to perform the certification process. Published in 1988, RIPv1 (Routing Information Protocol) uses something known as classful routing and a router hop count as a routing metric. Since there is no method for authenticating 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 several paths with the same load to a destination. Also, it sends triggered updates when metrics of a route have changed, allowing the network to converge faster, rather than wait for periodic updates. RIPv1 shows information such as: IP address, gateway, interface, metric, and/or timer. Portma... ... middle of paper ... ...buted database in order to store the names as well as address information for all public hosts on the Internet. DNS also assumes IP addresses are static, rather than dynamic. ARP, or Address Resolution Protocol, is used to map an IP address to a physical machine (i.e. Ethernet) address that has been recognized in the local network. A table, called an 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 conversions in both directions. For example, a host looking to obtain a physical address will do so by broadcasting an ARP request onto the TCP/IP network. The host on the network that possesses that IP address in the request will then reply with its physical hardware address. We can see an example of the initial broadcast in capture #67.