Category Archives: Admin

Relative time with the linux date command

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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Fail2ban fails to work, I built my own

Intro I’ve sung the praises of fail2ban as a modern way to shutdown those annoying probes of your cloud server. I recently got to work with a Redhat v 7.4 system, so much newer than my old CentOS 6 server. … Continue reading

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Reverse upper and lower case letters

Intro I am a look-at-the-keyboard typist! I can’t count the number of times I’ve begun an email with CAPs lock on, and found a nice correspondence looking like this: hI aNDRES,   i RE-CREATED THE SCRIPT. …hI aNDRES, i RE-CREATED … Continue reading

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Adding a swap file in Amazon AWS for CentOS

Intro I was running a new daemon on my server, factomd, to experiment with digital currency. It’s an old m1.small instance with only 1.7 GB of memory. The first few times I ran it it would 70000 or so blocks, … Continue reading

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Bluecoat ProxySG and DNS using edns seem incompatible

Intro Imagine your DNS server had this behaviour when queried using dig: $ dig drjohnstechtalk.com @146.201.145.30 ; <<>> DiG 9.9.2-P2 <<>> drjohnstechtalk.com @10.201.145.30 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: FORMERR, id: 48905 ;; flags: … Continue reading

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Use Raspberry Pi to explore mDNS

Intro I am confounded by the Bonjour field on my d-Link DCS-931L IP webcam. I should be able to use it to see my desired hostname, but it doesn’t take. Why? The details Having a Raspberry Pi on the same … Continue reading

Posted in Admin, Network Technologies, Raspberry Pi | Tagged , | 2 Comments

Tips for creating a PayPal Donate button for not-not-for-profits

Intro I am treating my blog as a public service, so I thought it would be appropriate to have a Donation link even though I have not incorporated as a 501c3 non-profit. Is it even possible? Can I keep my … Continue reading

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What I’m working on now: saving $69 a year on my certificate costs: Lets Encrypt

Intro I recently turned off my GoDaddy web site certificate and implemented one that cost me nothing. This will save me $69 per year. I wrote up my experience in this article: Idea for free web server certificates: Let’s Encrypt … Continue reading

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drjohnstechtalk now uses HTTP Strict Transport Security, HSTS

Intro I was reading about a kind of amazingly thorough exploit which could be done using a Raspberry Pi zero. Physical access is required, but the scope of what this guy has figured out and put together is really amazing. … Continue reading

Posted in Admin, Apache, Network Technologies, Security | Tagged | Leave a comment

Powershell winrm client error explained

Intro This particular Powershell error I came across yesterday is not well explained in other forums. I present the error and the explanation though not necessarily the solution. The details I recently received my new PC running Windows 8.1. On … Continue reading

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