Using CIDR 255.255.248.0 Subnet mask Subnet mask (binary) Network ID 11111111 11111110 11111 000 00000000 184.108.40.206 CIDR Entry 220.127.116.11 18.104.22.168 Subnet mask Subnet mask (binary) Network ID 11011100 01001110 10101 000 00000000 Starting network ID 11011100 01001110 10101 111 00000000 Ending network ID Class C Example
Guidelines for IP Addressing When assigning network and host IDs
Do not use 127 for a network ID
Do not use all 1’s for network and host ID
Do not use all 0’s for the network ID
Use a host ID that is unique to the local network ID
Internet Protocol version 6 (IPv6) was designed by the Internet Engineering Task Force (IETF) to overcome the limitations of IPv4 addresses
An IPv6 address is 128 bits in length
Example : 402A:0:2F7C:1:8BB:FFE3:728D:95A
addresses identify a single interface and are used when a single host sends a message to another single host.
addresses identify multiple interfaces when a single host is sending messages to many hosts.
addresses identify a single interface among many interfaces and are used when a single host sends a message to the nearest interface available.
addresses are available to any private network to use internally without the need to register the address. They are used for networks that aren’t connected to the Internet, or for networks that aren’t directly reachable because of a firewall.
address is 0:0:0:0:0:0:0:1 (also written as ::1). Loopback addresses identify a logical loopback interface, which allows the node to send packets to itself for testing purposes
Default gateway is an IP address of a router that is designated for any traffic for which the route is unknown
When a network router receives data, and it has an address for a default gateway, it follows this process:
The router looks at the IP header to determine the destination IP address.
The router determines whether the destination IP address is on the same network segment the data was received from.
If the destination IP address is for a different network, the router looks in its routing table for a route to that address.
If the router does not have a route listed for that destination network, it selects the default gateway address.
Public and Private IP Public addresses Private addresses
Do not have to be registered
Can be assigned by the network administrator
Are used on computers that are not accessed by the Internet 10.x.y.z 172.16-32.x.y 192.168.x.y
Are assigned by an ISP
Consist of unique class-based blocks
Are kept to a limited number
TCP/IP Protocol Functions
Internet Control Message Protocol (ICMP)
An Internet layer protocol that reports on the success or failure of data delivery
ICMP announcements provide critical information for troubleshooting network problems
Address Resolution Protocol (ARP)
An Internet layer protocol that obtains the MAC (physical) address of a host, or node, then creates a database that maps the MAC address to the host’s IP (logical) address
Reverse Address Resolution Protocol (RARP)
Allow the client to send a broadcast message with its MAC address and receive an IP address in reply
RARP was originally developed as a means for diskless workstations
Dynamic Host Configuration Protocol (DHCP)
An automated means of assigning a unique IP address to every device on a network
DHCP does not require a table of IP and MAC addresses on the server
DHCP does require configuration of DHCP service on a DHCP server
A terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol suite
Using Telnet, a TCP connection is established and keystrokes on the user’s machine act like keystrokes on the remotely connected machine
Telnet is notoriously insecure
Used to send and receive files via TCP/IP
FTP commands will work from your operating system’s command prompt