My Netwok Dictionary

You must assign a unique name to the router, as the first task of configuration. This is done in global configuration mode, using the following commands:

Router (config) # hostname MADRID
MADRID (config) #

The commands enable password and enable secret are used to restrict access to privileged EXEC mode. Enable password command is used only if you have not previously configured enable secret. It is recommended to always enable secret, as opposed to enable password, the password is always encrypted. Read the rest of this entry »

CEF = Cisco Express Forwarding
ACE = Access Control Entities
TCAM includes:
FM = Feature Manager
SDM = Switching Database Manager
VMR = Value Mask Result
LOU = Logical Unit Operational
PMD = Physical Medium Dependent
ASIC = Application-specific integrated circuits
VMPS = VLAN Policy Server Membersip
Tags TPID = Protocol Identifier Read the rest of this entry »

1. Locate the access point or wireless router in a central location
   Whenever possible, try placing the wireless router in a central location in our house. If instead we place the wireless router near a wall will weaken the signal more quickly.A priori not worry if you can not move the router to another location, there are still many things you can do to improve.
2. Do not place the router on the floor, or near walls or metal objects.
   The metal significantly affects the signal, producing unexpected rebound effects. The walls, and floors can affect whether a similar way inside is steel mesh, which is rather common in the way of building our country.The closer the router of these elements the weaker the signal that starts from that location.

Read the rest of this entry »

Knowing how to use and interpret the show commands allow the rapid diagnosis of faults. CCNA student should understand and assimilate the outputs of each of the shows one of the most important commands, these will give you the answer to more of a problem.

The user mode allows the execution of the show commands to a limited extent, from the privileged mode far outweighs quantity. Read the rest of this entry »

The interfaces of a router are part of networks that are directly connected to the device.
These interfaces must have an active and its corresponding IP address mask, as a host belonging to that network. The administrator must enable administrative interface with the command no shutdown if necessary the interface can be disabled with the shutdown command.

The screenshot shows a configuration of an ethernet interface:

Router> enable
Password :*******
Router # configure terminal
Enter configuration commands, one per line. End with CNTL / Z.
Router (config) # interface ethernet 0
Router (config-if) # ip address 192.168.1.1 255.255.255.0
Router (config-if) # no shutdown
Router (config-if) # description
Router (config-if) # description INTERFAZ_DE_LAN Read the rest of this entry »

ACL (Access Control List) can be used for:

• Packet security / filtering
• Defining “interesting” traffic for dial on demand routing (DDR) - only trigger dial-up line in case of “interesting” traffic
• QoS - not in But in CCVP CCNA, CCIP and CCNP
• NAT
• Control routing advertisement, through filtering routing updates

Creation - types of ACLs

• Standard IP ACLs
• Only source IP address
• Predefined ranges: 1-99, 1300-1999

rt # configure terminal
rt (config) # access list ACL # permit | deny hosts
rt (config) # access list 10 deny 172.16.0.15
rt (config) # access list 10 permit any
rt (config) # access list 20 deny 10.0.0.55 0.0.0.0
rt (config) # access list 10 permit 10.0.0.0 0.255.255.255 Read the rest of this entry »

In order to deliver message to potential damage or intrusion, there are several types of banners.

MADRID (config) # banner?
LINE c banner-text c, where 'c' is a delimiting character
exec Set EXEC process creation banner
incoming Set incoming terminal line banner
login Set login banner
motd Set Message of the Day banner Read the rest of this entry »

The main functionality of a router packet forwarding and filtering the same.
An alternative way to apply an ACL to filter packets based on destination is to create a series of static routes, making them point to null0, this technique is commonly described as a black hole routing or forwarding to null0.

Null0 is a pseudo-interface that works much like the null device of some operating systems (ie / dev / null) is always active and can not send or receive traffic. Being a pseudo-interface for the EFC is a bad interface, so a route that points to null0 is discarded and directly forwarding, CEF or dCEF no impact on the processor of the router.
For example:

interface null0
no icmp unreachables
!
ip route 127.0.0.0 255.0.0.0 null 0
ip route 193.121.1.254 0 255 255 255 255 null

In this case the no icmp unreachables is to prevent unnecessary responses when traffic is passed to null0.

We can assume that the black hole routing technique exploits the ability to forward the router to make the drop packets destined for networks that want to protect. Read the rest of this entry »