Currently viewing the tag: "layer 2"

Cisco tips: Track down communication issues – Part 1

By On March 15, 2010 · 3 Comments

You know how sometimes you plug in everything, configure device / ports and then the un-expected result is “not working”. Then you start to troubleshoot, which is a good point, but very important is where are you looking for the root cause of your issue.

A lot of people who have communication issue start by issuing a ping from one end to the other one. This is a good approach when somebody is reporting service issue (e.g. my webserver doesn’t work) as with the ping [...]

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Cisco: Layer 2 traffic filtering

By On November 27, 2008 · 1 Comment

Layer 2 traffic filtering can be very useful when you want to drop packets closer to
the source because you can do this on L2 next-hop which is the switch where the
devices are connected. Based on mac-address, Layer 2 filtering can be apply using
one of the two most common method: Port Security and MAC Access Groups.

Port Security is the more secure method of the two. To use it, map a switch port to the
specific MAC address of [...]

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Limit traffic on a Cisco switch L2 port with minimal configuration

By On November 14, 2008 · 1 Comment

Let’s say that somebody (or some task in a test) ask you to limit the inbound traffic on a switch Layer 2 port by using minimal configuration possible. I must say that in the first steps I failed this task miserable, but actually is very simple to do it.

I will use a plain layer 2 Cisco 2950 switch for this task. I observed that I could not implement this on a Cisco 3500XL. I don’t know if the IOS image was wrong, but I [...]

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