1. Well-known port numbers are contained in the file /etc/services on most Unix

Question

1. Well-known port numbers are contained in the file
/etc/services on most Unix systems. Use "grep" to determine
the port number(s) and transport layer protocol(s) (e.g. TCP,
UDP, etc.) used by the following servers/services:

(a) Echo

(b) Daytime

(c) FTP

(d) TFTP

Why is it important for servers of the same type (e.g., ftp
servers) to use the same well-known port number? Hint:
execute $ grep ftp /etc/services to find all lines in the
/etc/services file that contains the string "ftp".

2. What is the role of the portmapper in a client-server
application that uses Remote Procedure Calls (RPC)? Is it
important for the portmapper to be bound to a well-known
port? Is it important for RPC Servers to be bound to
well-known ports? Why?

3. RFC 5952 section 4 defines a canonical text format for usual
IPv6 addresses. Section 5 discusses "special" addresses.
Specify how the following addresses would be represented in
this format:

(a) 2001:DB8:0:0:0:1:0:1

(b) 2001:DB8:0:0:1:0:0:1

(c) 2001:DB8:0:1:1:1:1:1

(d) 2001:DB8:0:1:0:0:0:1

(e) 0:0:0:0:0:FFFF:129.130.10.5

Explanation / Answer

1

well-known port is typically used by a web server.

option A. is correct

2

TCP A connection-oriented transport layer protocol.

option b. is correct

3

UDP is a wireless suitable for applications that need fast, efficient transmission, hence UDP protocal is preferrable .

option a.

8)

TCP uses source and destination protocol ports in the header.

TCp is reliable.(There is absolute guarantee that the data transferred remains intact and arrives in the same order in which it was sent.)

UDP Used for multicast and broadcast.

UDP is a connection-less.

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