Network address of all zeros means "This network or segment".
Network address of all 1s means " all networks", same as hexadecimal of all Fs.
Network number 127 is reserved for loop-back tests.
Host (Node) address of all zeros mean "This Host (Node)".
Host (Node) address of all 1s mean "all Hosts (Nodes) " on the specified network.
The range of numbers from 18.104.22.168 to 22.214.171.124 is used for multicast packets. This is known as Class D address range.
The default subnet mask for
2. The range of numbers from 126.96.36.199 to 188.8.131.52 is used for multicast packets. This is known as Class D address range.
3. Telnet, FTP, and TFTP:
TCP/IP is the protocol used when you are Telnetting to a remote host. Telnet is used for terminal emulation that runs programs remotely.
FTP is used to transfer files. FTP is a connection-oriented protocol. It uses TCP/IP for file transfer.
TFTP (Trivial File Transfer Protocol) uses UDP. TFTP is a connectionless protocol.
4. A valid IP address on a host / node can't start with 127; 127.X.X.X is reserved for local loop back. A valid IP address can't be larger than 255 (in any octet), The maximum allowed value is 255 in any or combination of octets. For example, 150.206.256.31 is an invalid IP, since one octet exceeded the value 255. An example of valid IP is 184.108.40.206.
5. The number of distinct IP's required in a network are
a.One each per client computer
b.One each per server computer
c.One each per router interface.
For example, if there are 2 servers, 26 clients machines, and 2 router interfaces, the total number of IP addresses required are 30.
6. OSI 7 layers: The 7 layers of OSI model are:
7. HTTP is the protocol used for accessing the World Wide Web (WWW) services. HTTP operates over TCP/IP. TCP/IP is the protocol, which is used by all Internet applications such as WWW, FTP, and Telnet etc. IPX/SPX is proprietary protocol stack of Novell NetWare.
8. TCP/IP utilities:
NBTSTAT This utility displays current NetBIOS over TCP/IP connections, and display NetBIOS name cache.
NETSTAT Displays protocol statistics and current TCP/IP connections since the server was last booted
TRACERT This command is used to determine which route a packet takes to reach its destination from source.
IPCONFIG Displays Windows IP configuration information.
NSLOOKUP This utility enables users to interact with a DNS server and display resource records.
ROUTE This command can be used to display and edit static routing tables.
9. Important port numbers:
The port numbers used by different programs are as below:
FTP: Port #21
Telnet: Port #23
SMTP: Port #25
SNMP: Port #161
It is also important to know that FTP, Telnet, SMTP use TCP; whereas TFTP, SNMP use UDP.
10. Some of the important commands useful in trouble shooting TCP/IP networks:
I. Ipconfig: Displays TCP/IP configuration values, including IP address, subnet mask, and default gateway.
II. Ping: This command can be used to verify whether the target ip address or host name is present. You need to specify the target IP address or host name.
III. Route: Displays and manipulates route information.
IV. Tracert: Determines the route packets take to reach the specified destination.
DSL uses existing copper phone lines. The access speeds can be up to 9 MBPS. but has distance limitations and available in only certain exchange areas.
There are several categories of DSL:
ISDN specifies two standard access methods:
BRI (Basic Rate Interface):
PRI (Primary Rate Interface):
13. Tracert, Ping use ICMP as their base protocol. ICMP messages are carried in IP data grams.
14. SMTP is used to upload mail to the mail server. POP3 is used for downloading mail from a mail server to a client machine running POP3 client.
15. A firewall is a security mechanism, which prevents unauthorized access to a network or a resource on a network.
TCP is a full-duplex, connection-oriented protocol. It incorporates error checking as well. UDP (User Data gram Protocol): UDP is a thin protocol. UDP is a connectionless protocol. It doesn't contact the destination before sending the packet and doesn't care whether the packet is reached at the destination. UDP uses port number 6.
16. A DNS zone file contains the resource records for the part of the domain for which the zone is responsible. Some of the resource records are:
SOA (Start Of Authority Record): The first record in any zone file is the SOA record. The SOA file contains some general parameters such as contact e-mail of the person responsible for this zone file, the host on which zone file is maintained etc.
The NS Record (Name Server Record): NS Record contains the name servers for this domain. This will enable other name servers to look up names in your domain.
MX Record (Mail Exchange Record): MX record tells us which host processes mail for this domain.
Host Record (A Record): A host record is used to statically associate hosts names to IP addresses within a zone. The syntax for this is
<hostname> IN A <ip address of the host>
ex:NameServer1 IN A 220.127.116.11
Here 'NameServer1' is the host name and 18.104.22.168 is its ip address.
CNAME Record (Canonical name): These records allow you to use more than one name to point to a single Host. Using CNAME, you can host both WWW and FTP servers on the same machine.
Reverse Look up is useful when you want to implement security. Reverse look up ensures that the domain name is indeed the domain that it claims to be.
The correct format for Pointer record is
<ip reverse domain name> IN PTR <host name>
ex.: 22.214.171.124.in-addr.arpa. IN PTR services.yourcompany.co
Here the IP numbers are written in backward order and in-addr.arpa is appended to the end, creating a Pointer record.
17. Cookies: A cookie is a plain text file that sends out client information to the corresponding Web server, usually when the client makes a visit to the Web server. Disabling Cookies may result in improperly loaded Web pages.
Configuring the browser not to show pictures enable the Web pages to load faster.
A correctly formatted connection to access a Web site over a secure link will have "https://".
19. News Service:
By installing Internet News service, you can enable all group members to exchange threaded messages.
NNTP is a service. Users can connect to NNTP service using client software like Microsoft Internet Mail and News through TCP/IP.
20. XML (Extensible Markup Language) is a reduced version of SGML.
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