Tales From /proc

I'm a UNIX Sysadmin, specializing in Solaris and Linux. We should ALL know this stuff, but sometimes a trick or tip slips by, so every time I teach someone a neat trick (or someone teaches me a neat trick) it'll get shared here.

Saturday, April 11, 2009

CDP is useful, even if it's evil

This blog is all about the simple (or not so simple) little tricks we all either give or pick up throughout the day. Sometimes it'll be a simple trick, sometimes it'll be a complex nightmare.

So let's start with a simple one.
Props to Zach and Johnny for this one.

If you're running Cisco equipment, and have CDP enabled, this'll help you figure out:
Hostname of your switch
IP interface
Hostname and IP address of the mgmt interface
Cisco IOS Version
model number
Speed and Duplex config.


    tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000'


We can discuss the security implications of having CDP enabled in another blog post.
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About Me

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I am currently a Unix Systems Engineer for a cloud-based EMR company. I've been making large, complex systems "go" since 1995. I've worked with Novell and Exchange in the past, and now specialize in Solaris and Linux.