Tag Archives: trouble shoot

Discovering a Cisco Network with CDP (Part 2)

Part one of this two part series talked about walking out your network with CDP. This is useful when all you need to know is the topology of the network equipment its self. The next step in the process is to map out where servers or other hosts are located. The first way of doing this would be to log onto the host, capture packets, and look for a CDP packet that indicates the switch name and port that the host is connected to. This would require packet capture software on each system and is really not practical. The second … Continue reading

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Discovering a Cisco Network with CDP (Part 1)

If you have ever been dropped face first into an undocumented Cisco network with little Cisco experience you may have found yourself overwhelmed. Fortunately for admins who have no desire to tone cables or read long mac address tables there is a simple way to map out a network like this. The Cisco Discovery Protocol (CDP) is the answer. There are a few prerequisites but overall the process is fairly simple. First, CDP must be enabled on all of the devices and ports you would like to discover. This typically is the case as CDP is enabled by default on … Continue reading

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Fluke Link Runner

When looking for a simple, easy to use and easy to carry network tool I decided on the Link Runner by Fluke Networks.  The device its self is about the size of a typically smart phone and about twice as thick.  There are only three buttons on the device; a power button and a pair of soft keys.  The top of the device has a pair of Ethernet ports that made to the typical RJ-45 connector. I found the device really easy to use.  It was as simple as plugging in to both ports and look at the screen to … Continue reading

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Passive Sniffing on Windows

With Linux you can configure a sniffing only port relatively easy. Put it in promiscuous mode without an IP and sniff away passively. With windows, there is typically always an IP address assigned to an interface. If not statically assigned the interface will search for DHCP and will ultimately end up with an address in the 169 range if no address information is found. Either way there will be information from your machine showing up in a full, unfiltered packet capture. To get around this you will actually want to disable the TCP/IP stack for that interface. If this is … Continue reading

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