Port $81$ is a well known port number associated with:

a$.$ Telnet.

b$.$ FTP$.$

c$.$ SMTP$.$

d$.$ HTTP$.$

e$.$ None of the above.

The DNS server that receives a DNS query directly from a local DNS is:

a$.$ TLD$.$

b$.$ Root.

c$.$ Domain.

d$.$ Authoritative.

e$.$ URL.

The protocol that allows user to organize Email messages in folders and keeps user state across sessions is:

a$.$ IMAP.

b IGMP.

c$.$ POP.

d$.$ POP$3.$

e$.$ ICMP.

SMTP cannot be used by receiver agent to retrieve mail from receivers mail server because:

a$.$ SMTP can be used between servers only.

b$.$ SMTP is a push protocol.

c$.$ SMTP is a pull protocol.

d$.$ SMTP is not compatible with user agents.

e$.$ None of the above.

One of the following is an application that tolerates delay:

a$.$ Interactive games.

b$.$ Video streaming.

c$.$ Email.

d$.$ VoIP.

e$.$ None of the above.

With persistent HITP:

a$.$ Multiple objects are exchanged over the same TCP connection.

b$.$ Multiple objects are exchanged over the same HTTP session.

c$.$ Multiple objects are exchanged over the same packet switching connection.

d$.$ Multiple objects are exchanged over the same circuit switching connection.

e$.$ None of the above:

One of the following is a service that is not provided by TCP:

a$.$ Authentication.

b$.$ Flow control.

c$.$ Multiplexing.

d$.$ Congestion control.

e$.$ All of the above.