zeldor.biz

Linux, programming and more

Copyright © 2025
Log in

The Pledge of the Network Admin

February 6, 2011 by Igor Drobot Leave a Comment

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

Filed Under: Cisco, Linux Tagged With: Sysadmin

Trainig for CCNA 640-802

December 13, 2010 by Igor Drobot Leave a Comment

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

[Read more…]

Filed Under: Cisco Tagged With: CCNA 640-820, Cisco

Trainig for CCNA 640-802

December 12, 2010 by Igor Drobot Leave a Comment

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…]

Filed Under: Cisco Tagged With: CCNA 640-802, Cisco

Trainig for CCNA 640-802

December 5, 2010 by Igor Drobot Leave a Comment

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.

[Read more…]

Filed Under: Cisco Tagged With: CCNA 640-820, Cisco

Secure Cisco devices

October 19, 2010 by Igor Drobot Leave a Comment

Some cisco basic command to secure your device against logins.
You should execute this command always on your routers/switches.
DonĀ“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

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

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

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

Router(config)#enable password cisco Router(config)#enable secret class # No Plain-Text passwords more Router(config)#service password-encryption

Filed Under: Cisco Tagged With: Cisco Router Security, Secure Telnet

  • 1
  • 2
  • 3
  • Next Page »
Yeaaah Cookie! We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.Ok