Cisco – tcp-small-servers and udp-small-servers

blog, Cisco
For some truly unknown reason, Cisco's devices still have support for "small servers" or "simple services". Examples of these include echo, chargen, daytime and discard.  An attacker could possibly start a denial of service attack (DoS) against one or more network devices with those configured.  In this case; echo and chargen are to blame by allowing an attacker to cause  the chargen service to hit the echo services causing an endless loop of character generation and echo between the two hosts.  To disable this, simply enter the following commands: configure terminal no service tcp-small-servers no service udp-small-servers These commands can be run on nearly all IOS based Cisco equipment.
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Cisco Switching – switchport nonegotiate

blog, Cisco
Dynamic Trunking Protocol (DTP) is a standard feature of Cisco switches and allows two switches to dynamically configure interfaces interconnecting each other to be trunked ports.  DTP has 5 modes; Auto (default), On, Off, desirable and nonegotiate.  These 5 modes all have a purpose.  I have layed out the groundwork below: auto - The default setting allows the port to willingly convert to trunking, however, the port will not trunk unless the neighbor is set to on or desirable.  When two switches are connected together and set for auto, they will NOT trunk. on - This setting forces the port to be a trunk regardless of the neighbor's settings. off - This setting forces the port to not trunk, even if the neighbor is set to on. desirable - This…
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Cisco Command Reference

blog, Cisco
I was working on a client's network tonight and thought of about 10k topics to blog about.  All the commands on Cisco routers and switches.  The purpose of this would be to help remind me that the basics are not good enought and also expand your mind on what a command does, how to use it and possibly when to implement it.  If at any point I'm completely off my rocker, you know what to do :)
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New Asus eee PC

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Well, last Friday my wife and I added a new edition to the family; an Asus eee PC (XP Home, 1Gb Memory, 120 Gb Hard Drive).  We bid the highest on the computer at my companies yearly Christmas Party.  I really didn't want it at first but now that I've had a little bit of time on it, the computer is actually pretty fully functional.  There are a few minor issues that I see so far but overall, the computer is very very usable. So far this weekend I've really only had time to do some light surfing and software installs to get my core app's installed but I do have to say that it is very functional.  The size and weight are great, it's "fast enough" which I have…
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New Computer – 5.9 Vista Experience for under $400

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A few weeks ago I go the go ahead from my wife to build myself a new computer.  I have been rocking a P4 at home for quite some time...so long in fact that I just started using my work laptop as my home computer.  It wasn't horrible but definitely time to upgrade.  I knew I wanted to keep the cost down even though I think I could have gotten my wife to agree to nearly any reasonable price and I knew I wanted it to be FAST!! :)  That is a relative term but the items I did purchase SEEM very very fast to me.  It would blow my mind if I were to get all the high end stuff :). Case: Ultra X-Blaster ATX Black Mid-Tower Case Power Supply:…
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