Interframe Spacing:
Minimum spacing between 2 frames following each other on the line.
Time for media to stabilize and devices to process frame.
From the last bit of FCS to the first bit of the Preamble.
96 bit times (9.6 microsec)– time shortens as speed increases.
As we speed up, gap gets shorter as the bits get shorter.
Allows time for slow hosts to process frames.
A = Start Frame Field.
B = Address Field.
C = Type/Length Field.
D = Data Field.
E = FCS Field.
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Tags: switch, ip, study, router, 802.1q, interface
Configuring port security
A switch without port security allows attackers to connect to unused, ports and gather info or attack the network. All ports should be secured before a switch is deployed. Port security limits the number of MAC addresses allowed on port.
If you limit the number to 1 & assign a single MAC address only the pc attached is allowed to connect via that port, when that number is reached a security violation occurs.
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Security on a switch
eMac address flooding or overflow attacks
Switches learn a source MAC address from the MAC address table
If a frame enters a switch and it does not find the destination MAC address in the table, the switch acts like a hub and floods it out all ports. Mac address tables have a limited size.
MAC address flooding uses this limitation to bombard the switch with fake addresses until the table is full. The switch then enters fail-open mode and will act like a hub.
As a result, an attacker can see all of the frames passing through the switch.
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