Table of Contents
- 1 Does a switch have MAC address for each port?
- 2 Can a switch have the same MAC address in the switching table twice?
- 3 How many MAC addresses can a switch learn on one port?
- 4 How many MAC addresses does a switch have?
- 5 Can a MAC address table have more than one MAC address associated with an interface?
- 6 Can you change the MAC address of a device?
- 7 Why are multiple MAC addresses associated with the same port?
- 8 Does the switch store the same MAC address on multiple ports?
- 9 Can more than one Nic share the same MAC address?
- 10 How do I dynamically configure the MAC address of a port?
Does a switch have MAC address for each port?
Like all Ethernet interfaces, every port on a switch has a unique factory-assigned MAC address. However, unlike a normal Ethernet device that accepts only frames addressed directed to it, the Ethernet interface located in each port of a switch runs in promiscuous mode.
Can a switch have the same MAC address in the switching table twice?
No. A MAC address is an address of a unique NIC on the network, and each MAC address will only appear once in a switch’s MAC address table.
Do different ports have different MAC addresses?
An uplink port will have the mac addresses of everything downstream that was connected to by a device upstream. A port with only one adapter connected to it will show only one mac address, and no other port will show it.
How many MAC addresses can a switch learn on one port?
It says the maximum number of MAC addresses that it can learn is 8,192 MAC addresses. Again, depending on whatever hardware you’re using, that number could go up, could go down, but that’s hardware dependent. There’s no set number that a switch has to be able to support.
How many MAC addresses does a switch have?
It’s important to remember that every Ethernet frame contains two MAC addresses. The source address is always a unicast MAC address. The destination address will be either a unicast addresses, a multicast address or a broadcast address.
How many MAC addresses can a switch hold?
8,192 MAC addresses
The maximum number of MAC addresses that it can learn is 8,192 MAC addresses. Again, depending on whatever hardware you’re using, that number could go up, could go down, but that’s hardware …
Can a MAC address table have more than one MAC address associated with an interface?
You can have more than one MAC address on a switch port if: You have a switch connected to it. Could be another managed switch (like a Cisco) or an unmanaged switch (like a consumer Netgear or Linksys switch). You have a virtual server host attached to it with multiple virtual machines sharing the NIC.
Can you change the MAC address of a device?
The MAC address that is hard-coded on a network interface controller (NIC) cannot be changed. However, many drivers allow the MAC address to be changed. The process of masking a MAC address is known as MAC spoofing.
How many MAC addresses are possible?
281 trillion
The IEEE 802 MAC address originally comes from the Xerox Network Systems Ethernet addressing scheme. This 48-bit address space contains potentially 248 (over 281 trillion) possible MAC addresses. The IEEE manages allocation of MAC addresses, originally known as MAC-48 and which it now refers to as EUI-48 identifiers.
Why are multiple MAC addresses associated with the same port?
A switch can have multiple MAC addresses associated with a single port. This is common when the switch is connected to another switch. The switch will have a separate MAC address table entry for each frame received with a different source MAC address.
Does the switch store the same MAC address on multiple ports?
The Switch will not store the same MAC address on multiple ports. It will simply update its MAC address table with the location of the most recent frame arriving with the duplicate MAC address. If both hosts are transmitting constantly, that will cause the MAC address entry to bounce between the two switch ports (known as MAC flapping).
What is the MAC address of a spanning-tree port?
Each port on a switch that supports Spanning-Tree Protocol (802.1d) would have its own MAC address. The MAC address on each port would likely correspond to the port number (e.g. 2b:00 is port 0/0, 2b:01 is port 0/1, etc). The 2-byte STP port ID may be derived from a portion of the port’s MAC address.
If a there are more than one NICs on the same LAN that share the same MAC address, it will cause all sorts of communication issues. If not, what is the behavior when frame with known MAC comes from a different interface?
How do I dynamically configure the MAC address of a port?
You can statically configure all secure MAC addresses by using the switchport port-security mac-address mac_address interface configuration command. You can allow the port to dynamically configure secure MAC addresses with the MAC addresses of connected devices.