Category Archives: Admin

Great serial port concentrator: Raritan Dominion

Posted on November 26, 2018 by john | 4 views

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

Posted on November 16, 2018 by john | 12 views

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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Linux tip: how to enable remote syslog on SLES

Posted on July 27, 2018 by john | 43 views

Intro I write this knowing I still don’t know anything to speak of about syslog, but, sometimes you gotta act without knowing. I needed to send syslog to somewhere in a big hurry so I figured out the absolute minimum … Continue reading →

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The IT Detective Agency: the vanishing certificate error

Posted on April 30, 2018 by john | 44 views

Intro I was confronted with a web site certificate error. A user was reluctant – correctly – to proceed to an internal web site because he saw a message to the effect: I tried it myself with IE and got … Continue reading →

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The IT Detective agency: Some insights into 4096-bit SSL keys

Posted on April 26, 2018 by john | 46 views

Intro I was recently asked if a new certificate a web site is about to deploy would require any changes to our clients such as needing to import this certificate into their Java keystore. The details Well, I saved the … Continue reading →

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A taste of the Instagram API

Posted on April 16, 2018 by john | 46 views

Intro I always want to know more about how things really work behind the scenes, so I was excited when I overheard talk about how one company uses the Instagram API to do some cool things. An API is an … Continue reading →

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Measuring bandwidth on Checkpoint Gaia

Posted on March 21, 2018 by john | 64 views

Intro Sometimes you don’t have the tools you want but you have enough to make do. Such is the case with the command line utilities of the CLI of Checkpoint Gaia. It’s like a basic Linux. The company I consult … Continue reading →

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Linux Tip: too lazy to write a startup script? how to fake it

Posted on January 4, 2018 by john | 50 views

Intro systemd can be pretty formidable to master. Say you have your own little script you like to run but you don’t want to bother with inserting it into the systemd facility. What can you do? The details A simple … Continue reading →

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Server Name Indication and what it means for those with only a single IP address

Posted on October 27, 2017 by john | 105 views

Intro Sometimes everything is there in place, ready to be used, but you just have to either mistakenly try it, or learn it works by reading about it, because it may be counter-intuitive. Such is the case with Server Name … Continue reading →

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Relative time with the linux date command

Posted on October 13, 2017 by john | 211 views

The situation A server in Europe needs to transfer a log file which is written every hour from a server in the US. The filename format is 20171013-1039.log.gz And we want the transfer to be done every hour. How we … Continue reading →

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