Author Archives: john

Consumer Tech: amazing little Bluetooth adapter for your car

Intro My old car I decided finally needed a touch of Bluetooth connectivity. But how to do it without spending a fortune? The details I found this amazingly inexpensive gadget on Amazon that describes itself as follows: Handsfree Call Car … Continue reading

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Great serial port concentrator: Raritan Dominion

Intro Every now and then you find a product that is a leap ahead of where you were. Such is the case for us with regards to our product of choice for serial consoles. The old For Bluecoat (Symantec) proxy … Continue reading

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Counting active leases on an old ISC DHCP server

Intro Checkpoint Gaia offers a DHCP service, but it ias based on a crude and old dhcp daemon implementation frmo ISC. Doesn’t give you much. Mostly just the file /var/lib/dhcpd/dhcpd.leases, which it constantly updates. A typical dhcp client entry looks … Continue reading

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The IT Detective Agency: Cisco Jabber Carriage Return problem fixed

Intro Cisco Jabber is a pretty good IM application. I’ve seen how it is a true productivity enhancer. But not so much when it doesn’t work right. The symptoms I hadn’t rebooted for awhile. I had a bunch of open … Continue reading

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Latest spear phishing: your password plus extortion

Intro Three users that I know at a certain company have all received spear phishing emails worded very much like this one: The details I don’t really have many more details. One user described it to me as follows. He … Continue reading

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Voice and data vlans on one switch port, no vlan tagging: how does that work?

Intro We had a Cisco video conference unit pick up an IP from a data vlan whereas we expected it to pick it up from a voice vlan, where we had assigned it a static IP. What happened? The details … Continue reading

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Solution to this week’s NPR puzzle using simple Linux commands, again

Intro As I understood it, this week’s NPR puzzle is as follows. Think of a figure from the Bible with five letters. Move each letter three back, e.g., an “e” becomes a “b.” Find the Biblical figure which becomes an … Continue reading

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The IT detective agency: rogue IPv6 device messes up DHCP for entire subnet

Intro This was a fascinating case insofar as it was my first encounter with a real life IPv6 application. So it was trial by fire. The details I think the title of the post makes clear what happened. The site … Continue reading

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Where is my IP without the aggressive ads

Intro To locate where any IP address is located – known as geoip – you can do a simple duckduckgo search and get an idea, but you may also get sucked into one of those sites that provides a service … Continue reading

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What credit card fraud looks like

Intro A lost credit card. Or was it misplaced? Months later a whole bunch of “modest” charges appear all at once, a couple days after a few lower-value test charges were made. Thank goodness I had the presence of mind … Continue reading

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