• 01/22/2016
    7:00 AM
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Packet Analysis: HSRP, EIGRP, STP And CDP

In this video, Tony Fortunato covers packet analysis and key protocol considerations.

I am a huge fan of packet analysis to ensure your network devices are configured and behaving as you expect them to be.

In this video, I analyze multicast and broadcast packets, focusing on two Cisco routing protocols -- HSRP and EIGRP -- as well as Spanning Tree Protocol (STP) and Cisco Discovery Protocol (CDP). Specifically, I go over some of the protocol contents, what they mean and what you might want to tune.



As you go through packets, it's important  to ask yourself the following questions:

  • Does this protocol need to be on this segment?
  • Is this protocol properly configured?
  • Is there any further tuning that could be applied to this protocol?
  • Are there any security considerations for network protocols (i.e., clear text information)?


security considerations

Hi Tony -- Can you elaborate on what you mean by security considerations for network protocols?

Re: security considerations

some network protocols may be leveraged into redirecting network traffic. everything from rerouting to spoofing to man in the middle attacks fall into this general category. thats why i try not to advertise protocols, especially with default values facing untrusted networks.


HSRP captures are not very common when considered analysis of network protocols, unless you have large and little complex network with different scenario like R1 is the active router, R3 is the standby, and R2 is passive. R1 goes offline and R3 takes over as active after ten seconds. R2 is then promoted to the standby state.