By Matt Fahrner, on February 26th, 2017% 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 . . . → Read More: Installing Plixer’s “Scrutinizer” NPMD
By Matt Fahrner, on September 26th, 2016% 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 . . . → Read More: Fix Apple Bonjour with Cisco autonomous APs
By Matt Fahrner, on March 5th, 2014% Mostly for my own edification – use “ethtool”, eg:
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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: on Supports Wake-on: g Wake-on: g Link detected: yes |
You’ll note two important details about this output:
This NIC is gig capable but is only running at 100mbs. I claim to be running this as root, but any good sysad should be using “sudo” instead!
Anyway, simple command, but sometimes you forget them.
. . . → Read More: How to probe ethernet capabilities…
By Matt Fahrner, on September 4th, 2012% 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 . . . → Read More: Why is WLAN “signal quality” in negative decibels?
By Matt Fahrner, on December 20th, 2010% 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.â€
I think there’s more to it than just . . . → Read More: Larry Ellison on “Cloud Computing”
By Matt Fahrner, on December 4th, 2008% 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 . . . → Read More: Defaulting a Cisco interface…
By Matt Fahrner, on December 4th, 2008% 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 . . . → Read More: How to remove a VLAN from a port in CatOS…
By Matt Fahrner, on October 7th, 2008% 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 . . . → Read More: Where to find the Windows XP “hosts” file
By Matt Fahrner, on July 10th, 2008% 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 . . . → Read More: WPA versus WPA2?
By Matt Fahrner, on July 10th, 2008% 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 . . . → Read More: WPA resources
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