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Installing Plixer’s “Scrutinizer” NPMD
Plixer makes a good “Network Performance Monitoring and Diagnostics” (NPMD) application called “Scrutinizer“. NPMD, as Gartner calls it, mostly omeans, collecting, aggregating, and reporting on Netflow data. Plixer provides a VMware OVF for installation of a virtual appliance. I, however, ran into a few issues with the installation: I couldn’t get the install to work…
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Fix Apple Bonjour with Cisco autonomous APs
I purchased some used Cisco C1140 autonomous access points for my home network (autonomous meaning not lightweight or requiring a WLC). While everything seemed to be fine at first, later we noticed that printouts to our Canon laser printer were no longer working from our Macs. After some research I realized that the Macs were…
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How to probe ethernet capabilities…
Mostly for my own edification – use “ethtool”, eg: 1# Â ethtool eth0 Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation:…
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Why is WLAN “signal quality” in negative decibels?
If you use “iwconfig” on Linux to get statistics on your wireless LAN you’ll note that the “Signal Level” is expressed in negative decibels. On the surface that would appear confusing – how can decibels be negative?! Fortunately an anonymous poster explains at Toms Hardware: Absolute power of a signal is measured in wattage. The…
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Larry Ellison on “Cloud Computing”
Via SwissInfo: “The computer industry is the only industry that is more fashion-driven than women’s fashion,†Oracle founder Larry Ellison commented on cloud computing recently. “Maybe I’m an idiot, but I have no idea what anyone is talking about. What is it? It’s complete gibberish. It’s insane.†I think there’s more to it than just…
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Defaulting a Cisco interface…
One pain with Cisco IOS is trying to get a configured interface back to defaults. Half the time you don’t even remember what those were. If it’s a sub-interface you can “no” it, but you will still have configuration left behind: cisco(config)#no interface ATM1/0.1 Not all config may be removed and may reappear after reactivating…
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How to remove a VLAN from a port in CatOS…
I can never seem to remember how to “remove” a VLAN on a switch (eg: Cisco 6500) running the older CatOS. The new IOS based switches are much easier. Anyway, it’s actually quite simple, just force the port to VLAN 1 (assuming that is your default/native VLAN). For example if port 6/5 was set to…
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Where to find the Windows XP “hosts” file
Just like Unix you can add a static host to the Windows system. On Windows XP the file is usually found in the “intuitive” location here (may change depending on where you loaded Windows): C:\Windows\System32\drivers\etc This is also where the “lmhosts” file is found. The format is in standard ARPANET format. For more information see…
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WPA versus WPA2?
So what’s the difference? Not much or a lot depending on your opinion. WPA uses TKIP for key management, whereas WPA2 uses AES-CCMP. Usually depending on how the AP has been set up, you can use either (TKIP or AES-CCMP) interchangeably, thus using WPA or WPA2 as needed. Many older devices like those running Windows…
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WPA resources
When researching using WPA on Ciscos I ran into a lot of useful URLs as resources. If you’re in the same bind, you may find them helpful too: http://www.cisco.com/en/US/products/hw/wireless/ps4570/products_configuration_example09186a00801bd035.shtml http://articles.techrepublic.com.com/5100-1035-6148543.html http://articles.techrepublic.com.com/5100-1035-6148581.html http://i.t.com.com/i/tr/downloads/home/gou_secure-wireless-guide.pdf http://www.cisco.com/en/US/products/sw/secursw/ps2086/products_configuration_example09186a00801df0e4.shtml http://www.ccitraining.net/courses/cwls.shtml http://projectdream.org/publications/windows/eap-peap-cisco-windows-2003.html http://www.networkcomputing.com/1409/1409ws13.html http://www.cisco.com/en/US/products/hw/wireless/ps430/products_tech_note09186a008024aa4f.shtml http://cio.cisco.com/univercd/cc/td/doc/product/wireless/airo1100/accsspts/ap11icg/ivicgaut.htm http://www.networkworld.com/research/2002/0506whatisit.html http://tldp.org/HOWTO/html_single/8021X-HOWTO http://en.wikipedia.org/wiki/IEEE_802.1Q http://www.cisco.com/en/US/docs/wireless/access_point/12.2_15_JA/configuration/guide/s15vlan.html http://hardware.mcse.ms/archive80-2005-8-223677.html http://www.cisco.com/univercd/cc/td/doc/product/access/mar_3200/wlsnotes/cfwlsmod.htm http://www.cisco.com/univercd/cc/td/doc/solution/mblacrdg.pdf http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800a7af6.shtml http://www.cisco.com/warp/public/cc/pd/witc/ao1200ap/prodlit/wrsec_an.htm Not a pretty list, but still good to…
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What is 802.1x?
If you’re investigating things like enterprise WPA and/or NAC based network control you’ll probably run into the fact that it uses 802.1x protocol. So what is 802.1x? Basically the long and short of it is IEEE 802.1x is just a protocol to pass EAP over wired/wireless LANs. EAP on the other hand is just a…
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If using WPA-PSK, use a long key!
If you must use WPA-PSK (meaning WPA with a pre-shared key, rather than WPA using 802.1x authentication via Radius), make sure your key is sufficiently long. Ideally 20 characters or more. To quote: Robert Moskowitz’s article, “Weakness in Passphrase Choice in WPA Interface,” describes a theoretical attack on WPA passwords. The tools WPA-psk-bf, CoWPAtty and…