It has the same basic components as a standard desktop PC. Slide 4 4 Introduction to Routers A router is a special type of computer. Cisco calls its operating system the Cisco Internetwork Operating System or Cisco IOS. Slide 3 3 The Purpose of Cisco IOS As with a computer, a router or switch cannot function without an operating system.
A solid understanding of the IOS is essential for a network administrator.
So rather than fill this topic with baffling acronyms and unexplained concepts, I will just provide a brief outline of IKE and how it is used.1 Slide 2 2 Cisco IOS Cisco technology is built around the Cisco Internetwork Operating System (IOS), which is the software that controls the routing and switching functions of internetworking devices. I don’t have a background in cryptography, and I must assume that you, my reader, do not either. In fact, it is simply impossible to truly understand more than a real simplification of its operation without significant background in cryptography. IKE is defined in RFC 2409, and it is one of the more complicated of the IPsec protocols to comprehend. The primary support protocol used for this purpose in IPsec is called Internet Key Exchange (IKE). Before either AH or ESP can be used, however, it is necessary for the two devices to exchange the secret that the security protocols themselves will use. Anyone who isn’t in on the secret is able to intercept the information but is prevented either from reading it (if ESP is used to encrypt the payload) or from tampering with it undetected (if AH is used). Two devices that want to send information securely encode and decode it using a piece of information that only the devices know. IPsec, like many secure networking protocol sets, is based on the concept of a shared secret. It’s useful for troubleshooting connectivity problems on specific network segments. TCP/IP Traceroute (Tracert.exe) Determines the path to an internet address, and lists the time required to reach each hop. TCP/IP Route ( Route.exe) Displays and modifies entries in the local IP routing table. TCP/IP Ping (Ping.exe) Verifies IP-level connectivity to another internet address by sending Internet Control Message Protocol (ICMP) packets and measuring response time in milliseconds. TCP/IP NetBIOS Information (Nbtstat.exe) Displays statistics for the NetBIOS over TCP/IP (NetBT) protocol, NetBIOS name tables for both the local computer and remote computers, and the NetBIOS name cache. PathPing (Pathping.exe) Combines the functions of Traceroute and Ping to identify problems at a router or network link. This command-line scripting utility has a huge number of options, which are fully detailed in Help. Network Command Shell (Netsh.exe) Displays or modifies the network configuration of a local or remote computer that is currently running. Netstat (Netstat.exe) Displays active TCP connections, ports on which the computer is listening, Ethernet statistics, the IP routing table, and IPv4/IPv6 statistics.
Type net with no parameters to see a full list of available command-line options. Net services commands (Net.exe) Performs a broad range of network tasks.
Name Server Lookup (Nslookup.exe) Displays information about Domain Name System records for specific IP addresses and/or host names so that you can troubleshoot DNS problems. IP Configuration Utility (Ipconfig.exe) Displays all current Transmission Control Protocol/Internet Protocol (TCP/IP) network configuration values, and refreshes Dynamic Host Configuration Protocol (DHCP) and DNS settings. Hostname (Hostname.exe) Displays the host name of the current computer.
Get MAC Address (Getmac.exe ) Discovers the Media Access Control (MAC) address and lists associated network protocols for all network cards in a computer, either locally or across a network.