Question - Describe Application layer.
Answer
The application layer is located at the top of the TCP/IP protocol
layers. This one contains the network applications which make it possible to
communicate using the lower layers. The software in this layer therefore
communicates using one of the two protocols of the layer below (the transport
layer), i.e. TCP or UDP. In computer networking, an application layer firewall
is a firewall operating at the application layer of a protocol stack.[1]
Generally it is a host using various forms of proxy servers to proxy traffic
instead of routing it. As it works on the application layer, it may inspect the
contents of the traffic, blocking what the firewall administrator views as
inappropriate content, such as certain websites, viruses, and attempts to
exploit known logical flaws in client software, and so forth. An application
layer firewall does not route traffic on the network layer. All traffic stops
at the firewall which may initiate its own connections if the traffic satisfies
the rules.
Question - Define DNS.
Answer
The DNS translates Internet domain and host names to IP addresses. DNS
automatically converts the names we type in our Web browser address bar to the
IP addresses of Web servers hosting those sites. DNS implements a distributed
database to store this name and address information for all public hosts on the
Internet.
Question - Define Telnet.
Answer
Telnet is the main Internet protocol for creating a connection to a
remote server.
Question - Define SMTP.
Answer
SMTP - Short for Simple Mail Transfer Protocol, a protocol for sending
e-mail messages between servers.
|