Or
Monday, 14 December 2015
Friday, 4 December 2015
How to run .jlnp file on Ubuntu
To install javaws under Ubuntu 12.10/12.04 and Linux Mint 14/13 or older, open the terminal and run these commands:
Via the terminal, cd to the folder containing your plnp file and run this command:
sudo apt-get install icedtea-netx
Via the terminal, cd to the folder containing your plnp file and run this command:
javaws filename.jlnp
Cisco Switchport Port Security Feature
Overview
When configuring the security for a network, it is important to take advantage of the security features of all deployed devices. One of the security features available with Cisco switches (among other vendors) is switchport security.
The switchport security feature offers the ability to configure a switchport so that traffic can be limited to only a specific configured MAC address or list of MAC addresses.
Secure MAC Address Types
To begin with, there are three different types of secure MAC address:
Static secure MAC addresses—This type of secure MAC address is statically configured on a switchport and is stored in an address table and in the running configuration.
Dynamic secure MAC addresses—This type of secure MAC address is learned dynamically from the traffic that is sent through the switchport. These types of addresses are kept only in an address table and not in the running configuration.
Sticky secure MAC addresses—This type of secure MAC address can be manually configured or dynamically learned. These types of addresses are kept in an address table and in the running configuration.
Switchport Security Violations
The second piece of switchport port-security that must be understood is a security violation including what it is what causes it and what the different violation modes that exist. A switchport violation occurs in one of two situations:
The action that the device takes when one of these violations occurs can be configured:
Protect—This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, no notification action is taken when traffic is dropped.
Restrict—This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, a syslog message is logged, a Simple Network Management Protocol (SNMP) trap is sent, and a violation counter is incremented when traffic is dropped.
Shutdown—This mode is the default violation mode; when in this mode, the switch will automatically force the switchport into an error disabled (err-disable) state when a violation occurs. While in this state, the switchport forwards no traffic. The switchport can be brought out of this error disabled state by issuing the errdisable recovery cause CLI command or by disabling and reenabling the switchport.
Configuration
When configuring the security for a network, it is important to take advantage of the security features of all deployed devices. One of the security features available with Cisco switches (among other vendors) is switchport security.
The switchport security feature offers the ability to configure a switchport so that traffic can be limited to only a specific configured MAC address or list of MAC addresses.
Secure MAC Address Types
To begin with, there are three different types of secure MAC address:
Static secure MAC addresses—This type of secure MAC address is statically configured on a switchport and is stored in an address table and in the running configuration.
Dynamic secure MAC addresses—This type of secure MAC address is learned dynamically from the traffic that is sent through the switchport. These types of addresses are kept only in an address table and not in the running configuration.
Sticky secure MAC addresses—This type of secure MAC address can be manually configured or dynamically learned. These types of addresses are kept in an address table and in the running configuration.
Switchport Security Violations
The second piece of switchport port-security that must be understood is a security violation including what it is what causes it and what the different violation modes that exist. A switchport violation occurs in one of two situations:
- When the maximum number of secure MAC addresses has been reached (by default, the maximum number of secure MAC addresses per switchport is limited to 1)
- An address learned or configured on one secure interface is seen on another secure interface in the same VLAN
The action that the device takes when one of these violations occurs can be configured:
Protect—This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, no notification action is taken when traffic is dropped.
Restrict—This mode permits traffic from known MAC addresses to continue to be forwarded while dropping traffic from unknown MAC addresses when over the allowed MAC address limit. When configured with this mode, a syslog message is logged, a Simple Network Management Protocol (SNMP) trap is sent, and a violation counter is incremented when traffic is dropped.
Shutdown—This mode is the default violation mode; when in this mode, the switch will automatically force the switchport into an error disabled (err-disable) state when a violation occurs. While in this state, the switchport forwards no traffic. The switchport can be brought out of this error disabled state by issuing the errdisable recovery cause CLI command or by disabling and reenabling the switchport.
Configuration
Monday, 30 November 2015
CCNA2, Chapter 1 Summary
We have seen that the trend in networks is towards convergence using a single set of wires and devices to handle voice, video, and data transmission. In addition, there has been a dramatic shift in the way businesses operate. No longer are employees constrained to physical offices or by geographic boundaries. Resources must now be seamlessly available anytime and anywhere. The Cisco Borderless Network architecture enables different elements, from access switches to wireless access points, to work together and allow users to access resources from any place at any time.
The traditional three-layer hierarchical design model divides the network into core, distribution, and access layers, and allows each portion of the network to be optimized for specific functionality. It provides modularity, resiliency, and flexibility, which provides a foundation that allows network designers to overlay security, mobility, and unified communication features. In some networks, having a separate core and distribution layer is not required. In these networks, the functionality of the core layer and the distribution layer are often collapsed together.
Cisco LAN switches use ASICs to forward frames based on the destination MAC address. Before this can be accomplished, it must first use the source MAC address of incoming frames to build up a MAC address table in content-addressable memory (CAM). If the destination MAC address is contained in this table, the frame is forwarded only to the specific destination port. In cases were the destination MAC address is not found in the MAC address table, the frames are flooded out all ports, except the one on which the frame was received.
Switches use either store-and-forward or cut-through switching. Store-and-forward reads the entire frame into a buffer and checks the CRC before forwarding the frame. Cut-through switching only reads the first portion of the frame and starts forwarding it as soon as the destination address is read. Although this is extremely fast, no error checking is done on the frame before forwarding.
Every port on a switch forms a separate collision domain allowing for extremely high-speed full-duplex communication. Switch ports do not block broadcasts and connecting switches together can extend the size of the broadcast domain often resulting in degraded network performance.
The traditional three-layer hierarchical design model divides the network into core, distribution, and access layers, and allows each portion of the network to be optimized for specific functionality. It provides modularity, resiliency, and flexibility, which provides a foundation that allows network designers to overlay security, mobility, and unified communication features. In some networks, having a separate core and distribution layer is not required. In these networks, the functionality of the core layer and the distribution layer are often collapsed together.
Cisco LAN switches use ASICs to forward frames based on the destination MAC address. Before this can be accomplished, it must first use the source MAC address of incoming frames to build up a MAC address table in content-addressable memory (CAM). If the destination MAC address is contained in this table, the frame is forwarded only to the specific destination port. In cases were the destination MAC address is not found in the MAC address table, the frames are flooded out all ports, except the one on which the frame was received.
Switches use either store-and-forward or cut-through switching. Store-and-forward reads the entire frame into a buffer and checks the CRC before forwarding the frame. Cut-through switching only reads the first portion of the frame and starts forwarding it as soon as the destination address is read. Although this is extremely fast, no error checking is done on the frame before forwarding.
Every port on a switch forms a separate collision domain allowing for extremely high-speed full-duplex communication. Switch ports do not block broadcasts and connecting switches together can extend the size of the broadcast domain often resulting in degraded network performance.
Fundamental Switching Concept
The fundamental concept of switching refers to a device making a decision based on two criteria:
- Ingress port
- Destination address
The decision on how a switch forwards traffic is made in relation to the flow of that traffic. The term ingress is used to describe where a frame enters the device on a port. The term egress is used to describe frames leaving the device from a particular port.
When a switch makes a decision, it is based on the ingress port and the destination address of the message.
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