Changing your MAC address from the default is what we call MAC spoofing. This term has a negativeconnotation because its more popular uses are for improper activities, particularlywireless network hacking. However, MAC spoofing does have legitimate uses, suchas testing MAC filtering.
What Does Bia Stand For Mac
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The switch knows what traffic belongs to which VLAN even though it is using the same MAC on each vlan as it tags the traffic so that fact that it uses the same MAC is fine . As Riccardo said it saves resources .
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The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command./p>
This provides descriptions of dynamic router discovery mechanisms that are available to hosts. Many of these mechanisms do not provide the network resiliency required by network administrators. This can be caused when the protocol was not initially intended to provide network resiliency or because it is not feasible for every host on a network to run the protocol. In addition to what is listed, it is important to notice that many hosts only allow you to configure a default-gateway.
A large class of legacy host implementations that does not support dynamic discovery can configure a default router. To run a dynamic router discovery mechanism on every host, is not practical for a number of reasons, along with administrative overhead, processing overhead, security issues, or lack of a protocol implementation for some platforms considerations. HSRP provides failover services to these hosts.
When you use HSRP, a set of routers works in concert to present the illusion of a single virtual router to the hosts on the LAN. This set is known as an HSRP group or a standby group. A single router elected from the group is responsible for distribution of the packets that hosts send to the virtual router. This router is known as the Active router. Another router is elected as the Standby router. In the event that the Active router fails, the Standby assumes the packet-forwarding duties of the Active router. Although an arbitrary number of routers can run HSRP, only the Active router forwards the packets sent to the virtual router.
On a particular LAN, multiple hot standby groups can coexist and overlap. Each standby group emulates a single virtual router. The individual routers can participate in multiple groups. In this case, the router maintains separate state and timers for each group. Each standby group has a single, well-known MAC address, as well as an IP address.
When this standby router becomes active, stations on the same ring as the old active router need a new RIF in order to send packets to the new active router. However, since the standby (new active) router uses the same functional address as the previous active router the stations are not aware that they must send explorers for a new RIF. For this reason, the use-bia command was introduced.
To configure HSRP priority and preemption, use the standby [group] [prioritynumber] [preempt [delay [minimum]seconds] [syncseconds]]command. Refer to the HSRP Documentation for more information.
The use burned-in address (BIA) feature allows HSRP groups to use a burned-in MAC address of the interface instead of an HSRP MAC address. Use BIA was first implemented in Cisco IOS release 11.1(8). To configure HSRP to use the BIA, use the standby use-bia [scope interface] command.
The multiple HSRP (MHSRP) groups feature was added in Cisco IOS release 10.3. This feature further enables redundancy and load-sharing within networks and allows redundant routers to be more fully utilized. While a router is actively forwards traffic for one HSRP group, it can be in standby or in the listen state for another group.
In this case, it is often necessary to be able to specify the virtual MAC address that uses the standby mac-address command. The virtual IP address is unimportant for these protocols. The actual syntax of the command is standby [group] mac-address mac-address .
Support for syslog messaging for HSRP information was added in Cisco IOS release 11.3. This feature allows for more efficient logging and tracking of the current active and standby routers on syslog servers.
Before Cisco IOS release 12.1, the HSRP debugging command was relatively simple. To enable HSRP debugging, you would simply use the debug standby command, which enabled output of HSRP state and packet information for all standby groups on all interfaces.
A debug condition was added in Cisco IOS release 12.0(2.1) that allows the output from the standby debug command to be filtered based upon interface and group number. The command utilizes the debug condition paradigm introduced in Cisco IOS release 12.0, as follows: debug condition standby interface group . The interface you specify must be a valid interface that can support HSRP. The group can be any group (0 - 255).
You must enable standby debug order for any debug output to be produced. If you do not configure any standby debug conditions, then debug output is produced for all groups on all interfaces. If you configure at least one standby debug condition, then standby debug output is filtered by all standby debug conditions.
You can filter the debug output with the interface and HSRP group conditional debugging. To enable interface conditional debugging, use the debug condition interface interfacecommand. To enable HSRP conditional debugging, use the debug condition standby interface group command.
An interface debug condition applies only when you have set no standby debug conditions. HSRP debugging is further enhanced in Cisco IOS software release 12.1(1.3), based on the improvements that were made to the HSRP state table.
The HSRP authentication feature consists of a shared clear-text key contained within the HSRP packets. This feature prevents the lower priority router from learning the standby IP address and standby timer values from the higher priority router.
IP redundancy does not provide a mechanism for peer applications to exchange state information. This is left to the applications themselves and is essential if the applications are to provide stateful failover.
The ICMP protocol allows a router to redirect an endstation to send packets for a particular destination to another router on the same subnet, if the first router knows that the other router has a better path to that particular destination. As was the case for default gateways, if the router to which an endstation has been redirected for a particular destination fails, then the endstation packets to that destination were not delivered. In standard HSRP, this is exactly what happens. For this reason, it is recommended that you disable ICMP redirects if HSRP is turned on.
After the devices have been configured and network connectivity has been verified, you will use various commands to retrieve information from the devices to answer questions about your network equipment.Note: The switches used are Cisco Catalyst 2960s with Cisco IOS Release 15.2(2) (lanbasek9 image). Other switches and Cisco IOS versions can be used. Depending on the model and Cisco IOS version, the commands available and the output produced might vary from what is shown in the labs.Note: Make sure that the switches have been erased and have no startup configurations. If you are unsure, ask your instructor.
Note: MAC addresses are also called physical addresses, hardware addresses, or Ethernet hardware addresses.You will issue commands to display the MAC addresses on a PC and a switch, and analyze the properties of each one.Step 1: Analyze the MAC address for the PC-A NIC.Before you analyze the MAC address on PC-A, look at an example from a different PC NIC. You can issue the ipconfig /all command to view the MAC address of your NIC. An example screen output is shown below. When using the ipconfig /all command, notice that MAC addresses are referred to as physical addresses. Reading the MAC address from left to right, the first six hex digits refer to the vendor (manufacturer) of this device. These first six hex digits (3 bytes) are also known as the organizationally unique identifier (OUI). This 3-byte code is assigned to the vendor by the IEEE organization.To find the manufacturer, use the keywords IEEE OUI standards to find an OUI lookup tool on the internet or navigate to -oui.ieee.org/oui.txt to find the registered OUI vendor codes. The last six digits are the NIC serial number assigned by the manufacturer.
What is the MAC address for VLAN 1 on S1?Answers will vary based on the switch the student is using. Using the output from above, the answer would be 001b.0c6d.8f40.What is the MAC serial number for VLAN 1?Answers will vary based on the switch the student is using. Using the output from above, the answer would be 6d-8f-40.What is the OUI for VLAN 1?Answers will vary based on the switch the student is using. Using the output from above, the answer would be 00-1b-0c.Based on this OUI, what is the name of the vendor?Cisco SystemsWhat does bia stand for?Burned in address. 2ff7e9595c
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