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  • Email: did you become spam?

    A user’s email address might suddenly be downgraded to “spammer”: what it might look like and what can be done.

    The following is my understanding.

    Last fall (around eight months ago) I sent an email from an account I’d used for years. It bounced back. I’ve had that happen before, but rarely, and typically it turned out the problem was at the intended receiver’s end. However, this time seemed different, especially when I sent an email to a colleague and never got a reply. I was intrigued.

    I tried sending emails to some of my own, other email addresses. One gave a bounce back. The other received the email, but put it in Junk. Yet, that account had received emails from the sending one before, and had never done so. Something had changed.

    I realized that one can find headers on email that explain how the handling facilities perceive the email. In the receiving account, I checked the headers.

    Three headers of interest are DMARC, SPF, and DKIM. In broad strokes, DMARC comes up with the decision to label a message as spam or not, based on DKIM, SPF, and possibly other reasons.

    SPF is Sender Policy Framework, where a domain may list all servers whence they send emails. If an email comes from a server not listed by that domain’s SPF, it’s classified as spam or worse.

    DKIM is DomainKeys Identified Mail, and is cryptographic confirmation that an email came from the domain it says it did.

    DMARC is Domain-based Message Authentication and Reporting Conformance. It is the rule set that is used to classify an email, based on DKIM and SPF.

    DMARC, SPF, and DKIM may each have “PASS” or “FAIL.” FAIL can mean Spam or not even delivered, depending on local settings.

    In my case I checked the email headers and discovered that the SPF didn’t align: my emails were being sent from a new server that wasn’t listed with that domain’s SPF. I alerted my internet host and they cleared it up. As I recall, one of the headers cleared in a few hours, the last one within 48 hours (possibly within just 24 hours).

    After that, I sent a few practice emails that yielded good results at the receiving accounts. Next I sent a few emails to colleagues explaining I was testing the account. Things have been fine ever since, it seems.

    Source:

    askleo.com

    cloudflare.com

    -JS

  • LibreOffice Calc: Goal Seek

    Goal Seek can be used to solve equations.

    The following is how I understand it.

    Let’s imagine this scenario: cost is 1000 +0.44x, while revenue is 1.5x, where x is units sold. What, then, is the break-even point for units sold?

    In LibreOffice Calc, Goal Seek could be used to find the break-even point.

    In one cell (say a3), one types the formula 1.5*c3 – 0.44*c3 – 1000.

    It seems to me that the variable cell (in this case c3) needs to be initialized in order for Goal Seek to work. So, in this case, one might just enter 0 in c3.

    Next, in the Tools menu, find Goal Seek. It first asks what the Formula cell is, which in this case would be a3. Next, it asks what the Target value is: in this case, 0. Finally, it asks for the Variable cell: in this case, c3. Next, click OK or else press Enter.

    When I did so, Goal Seek replied that it had succeeded, and that the answer would be 943.396 (to 3 decimal places). It asked if I would like that value entered into the variable cell, and I clicked Yes. 943.396 then appeared in c3.

    Slick, eh?

    Source:

    help.libreoffice.org

    -JS

  • Web: subdirectory vs subdomain

    Subdirectories and subdomains can be used to organize web content. What are they, and how are they used?

    The following is my understanding.

    Let’s imagine a site called site101.tld101. In such a case, tld101 is the top-level-domain or tld. The domain, aka root domain, is site101.tld101. Furthermore, site101.tld101/blog is a subdirectory.

    Imagine then the address uppersite.site101.tld101. In that case, uppersite is a subdomain.

    Subdomains, it seems, are seen by search engines as separate sites from the domains they are hosted on. A subdomain, therefore, can be used to host separate content from what’s on the root domain. A subdirectory, on the other hand, is treated by search engines as part of the root domain site.

    Source:

    lovable.dev/guides

    namecheap.com

    -JS

  • Energy, accessories: charging banks

    You often see charging banks, aka power banks, among accessories. How are they used, and are they needed?

    The following is by my understanding.

    For this post, and commonly on this blog, phone refers to smartphone.

    My wife and I were recently in Vancouver, where we were bargain shopping, as usual. We found, in one store, a clearance deal on some power banks, which I call charging banks since one might charge their phone from one.

    Power banks I recall from the early 80s (but likely existed before that), advertised in computer magazines. The idea was that if you lose power, you lose everything in RAM. To prevent that, one could hook up their system to a power bank. Then, power from the wall could simultaneously maintain the bank at one hundred percent and also run the computer like normal. When power from the wall was lost, though, power could flow from the bank to the computer, so its power wouldn’t be interrupted. Back then, some ads I saw claimed they could run the computer for up to twenty minutes after power loss. One imagined that was easily enough time to save everything, close everything, and power off the computer normally. Then, one would wait for the power to return. Said power bank wasn’t meant to run the computer normally, just as a stopgap from power outage to safety. I never saw one of those power banks; only serious enterprises had them.

    Nowadays, of course, some people’s phones seem to run out of juice (aka energy) fairly often. It’s no wonder why: some phone apps can drain one percent of battery per minute, and it’s common for people to have numerous apps going at one time. One imagines having to replenish the phone’s energy one to several times per day, besides charging it in the evening at home (for instance).

    The charging bank is an obvious answer to the above scenario. I didn’t know how they are used exactly. The ones we found on clearance in Vancouver said, on the box, the energy capacity (10000mAh) and types of plugins on it (USB C and USB A). Nevertheless, the power banks seemed a very good deal, and we have two gen-Z sons, so we bought a couple of the charging banks. I hoped for more instructions inside the box.

    Yesterday my wife presented one of the charging banks to my younger son. He immediately opened the box. “Are there instructions?” I asked. “No,” he answered, “but I think I can figure this out.” He just took his phone charging cord (USB C both ends), plugged one end of it into the charging adapter at the wall, and its other end into the charging bank. “There: it must be charging now,” he said. I think there were lights on it that also suggested that. Later that day, away from home, he recharged his phone from it.

    One assumes both charging to the bank, then later receiving energy from it to his phone, would have been accomplished from the same port on the bank, since it only has one USB C port.

    Being a gen-Xer, I thought the idea of the USB C port being able to both accept energy from the wall, then later supply it to a device, was a lot to assume. To my son, however, it makes perfect sense. He seems very happy with the charging bank.

    Interesting, eh?

    Source:

    planhub.ca

    -JS

  • WordPress: Plugins: another let-down

    WordPress: Plugins, continued…

    The following is my take.

    I start about WordPress plugins in my post from June 2, 2026. I typically run a cache one, and sometimes that’s it.

    I thought about doing a post today about a plugin to make backups. Backups are important to safeguard content from errors, malfunctions, etc. Before doing any manual update, making a backup is likely a good idea. That’s what I do, anyway.

    So, I had a plugin installed which I was going to use to do a backup, then report about it.

    The plugin crashed: it just remained stuck at 0 percent completion. When I clicked the “Stop” button in its menu, I got a message back saying the process couldn’t be stopped.

    I logged into the server and stopped the plugin from there. Next, I deactivated, then deleted the plugin.

    I never keep plugins around that don’t stop when I click “Stop.”

    A plugin isn’t needed to make a backup of a WordPress site; a backup can be created manually. However, some plugins, assuming they work, might make it more convenient.

    Not in this case, apparently:)

    -JS

  • Household technology: overhead door tweak

    An unreliable overhead door needed investigation.

    The house I live in is over 30 years old. In the main, it’s fine, but some things need fix-ups every so often. Such it was with the overhead garage door opener, which had become quite unreliable.

    I did some inquiries and came to suspect the problem wasn’t the controlling device, but rather the antenna. Realizing what it must be on the unit, I also observed that, from the driveway, it was behind the opener. It was somewhat amazing it had been working at all.

    Even re-orienting the antenna, it still wasn’t long enough to provide enough exposure towards the driveway. I stripped back some of its insulation, then twisted another wire onto it to lengthen it by perhaps eight inches. It’s pointing straight down, reaching to perhaps 75 inches above the garage floor.

    With that amount of extension, there seems enough antenna to pick up the signal from the controller: the garage opens and closes much more reliably, at least for now.

    Source:

    YouTube: Word of Advice TV: Garage Door Remote Not Working – 5 Most Common Reasons Why

    YouTube: Kite Army: Garage Door Opener | How to Extend Range

    -JS

  • Computer constructs: caches, part 0

    What is a cache? What are some types of them?

    The following is my understanding about caches.

    In French, cacher means “to hide.” However, in woods-person terms, “to hide” and “to store” are closely related, because storing food means hiding it from foragers. Hence, a cache is, functionally, a place to store stuff.

    In computer terms, a cache typically means a place where results are stored so the CPU doesn’t have to figure them out again. Rather, said responses can just be brought from storage immediately. Cache storage needs to be fast in order to effectively save time.

    Types of caches have evolved. They may be classified on how fast they are to retrieve from, as well as by what they store. In the web world, for instance, page caches store pre-built pages that are called for often. Object caches store answers to database queries, for instance, that are often requested. Opcode caches store parts of computer programs that are run often. In each case, the code has been refined into a finished solution, or closer to one, so the CPU doesn’t have to start from scratch to respond to a request.

    On a website that delivers complex content, such as a WordPress site might become, all three of the caches described above might be used. Typically, without a cache, the content may be delivered noticeably slower compared to when a cache is used. At high levels, caches can be calibrated to be even more efficient.

    Source:

    php.net: OPcache

    gxmediagy.com: “OPcache, Object Cache, and Page Cache: The Three Layers That Make Websites Feel Instant”

    -JS

  • WordPress: Plugins, part 0

    What one veteran WordPress user thinks about plugins, part zero.

    The following is my understanding, opinion, etc.

    I’ve been using WordPress since 2012. It’s a great platform. AI tells me that, as of today, around 43 percent of the web runs on WordPress.

    At surface level, WordPress is easy to load up and post from. Next, some users want to manage their content, enhance how it’s displayed, reorganize it, etc. Often, that’s where plugins come into play.

    I recall learning about plugins and using a few in my early days. They seemed great – one would load a plugin, then get access to surprisingly convenient utility.

    In my case, there were two such plugins, each offering something I could have done myself but only after a lot of programming. Both plugins were free, and offered such utility with minimal effort. I really enjoyed using them.

    One crashed fairly early on – it just stopped working. It didn’t seem to make much of a mess, nor did it affect many posts. What it did, I admit, seemed too good to be true. When it stopped working, I just continued without it.

    The other plugin was key for several in-depth posts. When it broke, it made a mess, since it was a presentation plugin. Once it failed to encode the content meant for it, the raw code was exposed. While it all seemed harmless enough, it was unsightly and made those posts useless. I stopped using that plugin, or any like it.

    Both that plugin, and the one that broke earlier, were free. Paid ones might have more and better support. However, I think a user would have to be quite attached to a plugin to keep using it after its breakage crashed their site.

    Nowadays, I typically use a cache plugin (more about that later), and sometimes nothing else. I’ve even had a cache break on me, giving an error message where my site should have been displayed – not fun, but I recovered from it.

    That said, many WordPress users seem to depend on and celebrate all kinds of plugins. WordPress is PHP-based, so the potential utility of a plugin is virtually unlimited.

    I plan to continue about WordPress plugins.

    -JS

  • Formats: XML

    What is XML? It’s a document format.

    The following is how I understand it.

    XML is used to format documents that need to impart specific information. Somewhat like html, XML places the information between tags that classify it.

    An XML document will typically start with a document declaration such as <?xml version=‘1.0’ encoding=‘UTF-8’?>. For that declaration only, the question marks serve to nest it.

    Next, the XML document needs what’s called a root element. All other elements will appear within the root element. The root element must be unique at that level; there can’t be two.

    Finally, each element, including the root, must have an opening and closing tag. Tags can be nested. An opening tag and closing tag look like this:

    <mood_tag>happy</mood_tag>

    So, a very simple xml document might be like so:

    <?xml version=‘1.0’ encoding=‘UTF-8’?>

    <the_root>

    <an_element>Element1</an_element>

    <another_element>Element2</another_element>

    </the_root>

    XML code can be checked for following the rules (aka validated) at the site JSON formatter: XML Validator.

    Source:

    ibm.com: XML Syntax Rules

    -JS

  • Web: Cookies, part 0

    Beginning ideas about cookies.

    Here’s my understanding about cookies:

    Cookies are bits of information stored on one’s browser. When you visit a site, that site may store one or more cookies on the browser. Then, when you return later, that same site can retrieve that information.

    Cookies can be retrieved to help the browser reload the page in the state you seemed to want it. They can also store information you entered on the site, such as a username and/or password. That way, as one navigates pages of the same site, one needn’t keep signing in each time.

    A third party advertiser on a site the browser visits may also be able to store a cookie on that browser. However, to my knowledge, a site can only recall its own cookies, not ones from other sites.

    Tracking cookies, as they are called, are used to find out other sites a browser visited. However, because a site can only recall its own cookies from the browser, tracking cookies only work when there is common ownership among the sites somehow. That could happen, for instance, if the same advertiser has ads on several sites the browser visits. In such a case, that advertiser might be able to retrieve cookies it put from all those sites, therefore realizing that browser visited them all.

    Cookies likely aren’t that much of a menace, but things can get a bit overdone sometimes, just on principle. I recall, with one cookie permission, a site mentioning its 841 partners would be sharing information based on cookies that would be placed on my browser. Seriously?

    Source:

    YouTube: Ask Leo! “What Are Tracking Cookies, and Should They Concern Me?”

    -JS