chapter 8

Check all features/services ESMTP allows/offers.

-Encrypts and transfers ASCII text -Used to encrypt and transfer encrypted data from the Sender User Agent to the Message Transfer Agent - one more (maybe to encrypt and transfer data form to a MTA to MTA)

Check all features/services SMTP allows/offers.

-Used to transfer data in plain from the Sender User Agent to the Message Transfer Agent -Used to transfer data in plain from to a Message Transfer Agent to a Message Transfer Agent -Transfers plain ASCII text

For DNS, these domain names are generic .

.com. edu. net. org. museum

Using DNS, each zone (.e., edu, cisco.com, cs.washington.edu, tamu.edu, cs.tamu.edu, .....) must have at least ________ name server(s).

1

Assume that the local name server just started (cache empty).Suppose a DNS client must resolve the host name toto.jill.acm.org. Assign to each name server on the left a sequence number n based on the order it is queried. The first queried name server must be assigned the sequence number 1. Assign 99 to a name server that is not queried. root Nacm Norg Nwas Local name server

2 4 3 99 1

Assume that the local name server just started (cache empty). The local name server just resolved the hostname tatiana.robot.cs.washington.edu and right after a DNS client must resolve the host name toto.robot.cs.washington.edu. Assign to each name server on the left a sequence number n based on the order it is queried. The first queried name server must be assigned the sequence number 1. Assign 99 to a name server that is not queried.NcsNedurootNwasLocal name server

2 99 99 99 1

SMTP binds to Port Number _______________. POP3 binds to Port Number _______________. IMAP binds to Port Number _______________.

25 110 143

The email architecture involves ________ main operations.

3

The email architecture has ________ components.

4

Assume that the local name server just started (cache empty). The local name server just resolved the hostname tatiana.edu and right after a DNS client must resolve the host name toto.robot.cs.washington.edu. Assign to each name server on the left a sequence number n based on the order it is queried. The first queried name server must be assigned the sequence number 1. Assign 99 to a name server that is not queried. Ncs Nedu root Nwas Local name server

4 2 99 3 1

A DNS server binds to Port # _______.

53

Matching. Assume that the local name server just started (cache empty). The local name server just resolved the A) hostname ______________ and right after a B) DNS client must resolve the host name ____________________ Assign to each name server on the left a sequence number n based on the order it is queried. The first queried name server must be assigned the sequence number 1. Assign 99 to a name server that is not queried.

A) Given one name a.b.c.d 1. Local name server 2. root 3. d is queried first then c, b, a B) Given two names [1. a.b.c.d 2. f.e.c.d] 1. Local name server 2. compare first and second word, if first word already covered a section don't include. 3. If it hasnt, first query word right before the different one[c], then the different[e, a] *if already found all, query last found{a.b.c.d to e.b.c.d- query local name server and then b

Apart the difference in the layers where they perform, DNS is a service most similar to the _________ service.

ARP

Most applications on any host on the Internet will use the service offered by this protocol.

DNS

Check all applications that use UDP.

DNS TFTP(trivial file transfer protocol)

Most hosts on the Internet will have these protocols active on them.

DNS client DHCP client TCP IP UDP

In the OSI reference model, an instance in the network layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

Data Link

Match. Assume that the local name server just started (cache empty). The local name server just resolved the hostname tatiana.washington.edu and right after a DNS client must resolve the host name toto.robot.cs.washington.edu. Assign to each name server on the left a sequence number n based on the order it is queried. The first queried name server must be assigned the sequence number 1. Assign 99 to a name server that is not queried.

Local name server Nwas Ncs

In the TCP/IP reference model, an instance in the internet layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

NONE

Check all applications that TCP and UDP uses.

None

Using DNS, each domain name (i.e., edu, cisco.com, cs.washington.edu, tamu.edu, cs.tamu.edu, .....) must have at least ________ name server(s).

None

Check the application layer protocol(s) used for the delivery of an email from a Message Transfer Agent to a Receiver User Agent.

POP3 IMAP

This Internet pioneer was the first to invent (mention) the concept of a packet (packet switching).

Paul Baran

Check all elements somewhat related to DNS. "Related" means that they interact with, use, are used by, or identify DNS.

Port 53 IP UDP

Match each protocol with its original RFC. HTTP 1.1 TCP UDP DNS IP SMTP

RFC 2068 RFC 793 RFC 768 RFC 1034 RFC 791 RFC 821

These Internet pioneers made the Internet stable (free from congestion collapse).

Raj Jain Van Jacobson

Check components that are part of the email architecture presented in class..

Receiver User Agent Message Transfer Agent Mailbox Sender User Agent

For DNS, the top-level domains are run by __________________ appointed by ICANN.

Registrars

Check the application layer protocol(s) used for the submission of an email by the Sender User Agent to the Message Transfer Agent.

SMTP -one more(maybe esmtp)

Check the application layer protocol(s) used for the transfer of an email from a Message Transfer Agent to another.

SMTP ESMTP

In general, these protocols/services may use directly or indirectly a DNS client.

SMTP client (2 more) maybe SMTP sever and DNS server

Check the main operations performed to send and receive emails.

Submission Transfer Delivery

Check the transport layer protocol(s) used for the delivery of an email from a Message Transfer Agent to a Receiver User Agent.

TCP

Check the transport layer protocol(s) used for the submission of an email by the Sender User Agent to the Message Transfer Agent.

TCP

Check the transport layer protocol(s) used for the transfer of an email from a Message Transfer Agent to another.

TCP

In the OSI reference model, an instance in the session layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

Transport

In the TCP/IP model, consider an HTTP request m. The first header added to m will be a header belonging to the ________ layer.

Transport

A DNS server/client uses ________ at the transport layer.

UDP

Match these protocols in the TCP/IP reference model to the (transport) port number they use. Choose "N/A" if the protocol does not use a port number.

UDP -- N/A IMAP -- 143 TCP -- N/A HTTP -- 80 DNS -- 53 Telnet -- 23 IP -- N/A TFTP -- 69 SMTP -- 25 FTP -- 21 ssh -- 22

Check all features that TCP offers while UDP does NOT.

congestion control error correction (retransmissions) Reliable in-order delivery Flow control

UDP uses

error detection and addressing

In the OSI reference model, an instance in the transport layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

network

For DNS, the domain name "cisco" is defined under the domain .com (to form cisco.com). These domains can not use the domain cisco under them.

none

DNS client port number

none?

In the OSI reference model, an instance in the application layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

presentation

In general, an HTTP _________________ is longer than a(n) ________________.

response: HTTP request

In the TCP/IP model, an instance in the application layer wants to send a data unit m. The first header added to m will be a header belonging to the ________ layer.

transport

DNS stands for _____ _____ _____ .

Domain Name System

Check all applications that use TCP.

FTP HTTP SMTP POP3 ssh

DNS is a service that maps ______________ to ______________.

Host names : IP Addresses

Match these protocols in the TCP/IP reference model to some protocol they usually use in the layer below theirs. IP POP3 UDP FTP DNS IMAP TCP TFTP SMTP HTTP

IEE 802.11 TCP IP TCP UDP TCP IP UDP TCP TCP

A DNS server uses ________ at the network (internet) layer.

IP

Match these protocols to their layers in the TCP/IP reference model. IP UDP TCP HTTP DNS POP3 UDP FTP SMTP

IP -- Internet (network) UDP -- Transport TCP -- Transport HTTP -- Application DNS -- Application POP3 -- Application FTP -- Application SMTP -- Application

This Internet pioneer was an editor or an author for the original RFCs specifying IP, UDP, TCP, and SMTP

Jon Postel