Category Archives: Admin

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

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

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. … Tired of the … 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

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