Default Gateway and Subnet mask

Default Gateway - In a network using subnets, the router that forwards traffic to a destination outside of the subnet of the transmitting device.

Subnet mask - used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network.

Preferred and Alternate DNS server - This is a server that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned. So, it will check the "Preferred" DNS server first, if it can't translate the name, then it will hit the "Alternate" DNS server.


1. How do you determine what Class network it is?
2. How do you determine what the correct subnet mask of a network should be?
3. Can you explain the Default Gateway a bit more and how to determine what the Default Gateway should be under the TCP/IP Properties?
4. Explain a bit more on what a Subnet mask does
5. How to determine what the Preferred/Alternate DNS Server should be?
6. Are these all as simple as going and doing a ipconfig /all on the server to determine the addresses of these? And if so, how does the server get these addresses? Are they set by the router or are they set manually when you set up a server?

Answers :-
1. If it is a Local Area Network, the network administrator will determine the Class. This is based on how many hosts will be connecting and how many subnets are needed. There are 5 Classes: A, B, C, D, and E. Class D and E are used for multicasting, and are not used. Now you have a choice of A, B, or C. Class A's range is 1.0.0.1 to 126.0.0.0 This range allows up to 126 networks and 16777216 hosts.
A Class B Ip range is 128.0.0.0 to 191.254.0.0 which allows 16384 networks and 65536 hosts. A Class C range is 192.0.0.0 to 223.255.255.254 which allows 2097152 networks and 254 hosts on each of the networks.
Within a LAN, there are Private IP addresses that are set aside just for this purpose. They are 10.0.0.1 to 10.255.255.254 for a class A, 172.16.0.1 to 172.31.255.254 for class B and 192.168.0.1 to 192.168.255.254 for class C. Most Network Admins use 10.0.0.1 or 192.168.0.1.