Linux, programming and more
Never heard about it:
This is my network.
It is mine
or technically my employer’s,
it is my responsibility
and I care for it with all my heart
there are many other networks a lot like mine,
but none are just like it.
I solemnly swear
that I will not mindlessly paste from HOWTOs.
from Peter N. M. Hansteen
Q: Which three application layer protocols use TCP? (Choose three.)
A: SMTP
A: FTP
SNMP
A: HTTP
TFTP
DHCP
Q: Which two application layer protocols use the UDP protocol? (Choose two.)
Telnet
A: SNMP
SMTP
SQL
A: TFTP
Q: What are two functions that occur at the Internet layer of the TCP/IP model? (Choose two.)
establishment of logical connections between source and destination hosts
A: end-to-end flow control
determination of best paths through the network
definition of the procedures used to interface with the network hardware
A: packet switching
Layer 5 and Layer 6 OSI model functions
Q: What are three examples of TCP/IP application layer protocols? (Choose three.)
A: a terminal emulation protocol that supports remote console connections with various network devices
A: a protocol responsible for transporting electronic mail on TCP/IP networks and the Internet
A: a protocol that exchanges network management information between a network device and a management console
Q: Refer to the exhibit. The exhibit shows simplified protocol data units from different OSI model layers. Which three statements are true
about the PDUs and the encapsulation process?
A: PDU #1 is a frame.
A: PDU #3 is a segment.
A: The order in which these PDUs are created during the encapsulation process is 3, 4, 1, 2.
[Read more…]
Q: What is the purpose of the Spanning Tree Protocol (STP)?
A: prevents Layer 2 loops
Q: What creates a loop-free path through a switch network?
A: Spanning Tree Protocol
Q: Which statement is true regarding states of the IEEE 802.1D Spanning Tree Protocol?
A: Ports listen and learn before going into the forwarding state.
Q: Which industry-wide specification was developed to decrease the time that is needed to move to the forwarding state by switch ports that are operating in a redundantly switched topology?
A: RSTP
Q: Refer to the exhibit. Which switch will be elected the root bridge and which switch will place a port in blocking mode?
A: SW4 will get a port blocked.
A: SW3 will become the root bridge.
Some cisco basic command to secure your device against logins.
You should execute this command always on your routers/switches.
Don´t forget to replace the “cisco” password!
Set a console password to cisco:
1 2 3 | Router(config)#line con 0 Router(config-line)#login Router(config-line)#password cisco |
Set a telnet password:
1 2 3 | Router(config)#line vty 0 4 Router(config-line)#login Router(config-line)#password cisco |
Stop console timing out:
1 2 | Router(config)#line con 0 Router(config-line)#exec-timeout 0 0 |
Set the enable password to cisco:
1 2 3 4 | Router(config)#enable password cisco Router(config)#enable secret class # No Plain-Text passwords more Router(config)#service password-encryption |