Another one for the Things To Remember category … after creating a new Amazon Linux 2 instance, it’s important to update firewalld to allow http & https traffic.
Continue readingAmazon Linux 2 & Firewalld
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Category Archives: Things to remember…
Thunderbird and ‘reply-to’
This is another one in the ‘Things to remember’ category.
For some reason, by default, Thunderbird does not use the ‘Reply-to’ header in emails. This headers tells mail software what address that replies should be sent to. It’s commonly used for mailing lists so that replies are sent to another address, such as the the mailing list itself, instead of the address that sent the message.
To change the default Thunderbird behavior, you have to tweak a setting.
Continue readingOpenSSL error 1408E0F4
Recently I encountered a problem with SSL on one of my websites … some web browser could not connect securely.
When I ran a test from Linux, I got the following error:
OpenSSL: error:1408E0F4:SSL routines:ssl3_get_message:unexpected message
After a bit of digging, I found that a recent upgrade to the certbot-auto tool, that creates LetsEncrypt certificates, caused the problem.
The fix was to modify /etc/letsencrypt/options-ssl-apache.conf so that the SSLSessionTickets setting was set to on.
Postmaster Resources
This post is as much to help me remember as it is to help other people.
Below is a list (not comprehensive) of the postmaster resource pages for some of the major email providers.
| Microsoft / Outlook | https://postmaster.outlook.com |
| https://postmaster.google.com/ | |
| Yahoo | https://help.yahoo.com/kb/postmaster |
| Comcast | https://postmaster.comcast.net/ |
| AOL | https://postmaster.aol.com/ |
On these sites you can get information about how the provider handles spam, feedback loops, blacklists, whitelists, etc.
Very useful for those managing mailing list servers.
Your ISP’s DHCP does not function properly
As part of my migration to the cloud, I terminated the Comcast Business internet service and switched to Xfinity internet.
When I initially signed up for the Xfinity service, I got their cable modem / router / wifi appliance. My plan was to get my own cable modem eventually because Xfinity charges $13 / month to lease the appliance.
I was at Best Buy and saw that cable modems weren’t expensive, so I decided to purchase a mid-level model (Netgear CM600) so I could save the lease fee. The CM600 would pay for itself in about 8 months.
It took a while to get setup … and there were a few false starts, but eventually I got it working connected directly to my MacBook.
I ran into a problem when I switched the CM600 over to my ASUS RT-5300 wifi router.
I kept getting the message “Your ISP’s DHCP does not function properly” on the ASUS network map page.
Continue readingRestore Screen Saver Association
If you’re like me, you probably install & uninstall software on your system on a a fairly frequent basis.
One of the things that really annoys me when I install software is when it automatically takes over a file extension association that was previously registered with the system.
This happened a while ago when I installed some IBM software for work … the .scr extension was taken over completely. ‘.scr’ is normally associated with windows screen savers, but now it’s associated with the IBM CODE/400 editor (which I don’t use).
After digging around a bit, I found an easy way to fix this. Just execute the following command: ‘assoc .scr scrfile‘
This restores the association of .scr files to the system’s screen saver mechanism.
Global Warming
This video was found on YouTube by someone who subscribes to my CPF0000 mailing list. Quite enlightening, don’t you think?[kml_flashembed movie="http://www.youtube.com/v/bDsIFspVzfI" width="425" height="350" wmode="transparent" /]
Here’s my contribution to spreading the word.
Is that my laptop?
Picture this … you’re going through the security checkpoint at an airport … you’ve taken your laptop out of your bag and sent it through the x-ray machine.
You get through the metal detector … and find TWO laptops, identical in appearance, at the end of the x-ray machine.
Which one is yours?
Something like this happened a number of years ago … I was traveling for business, went through security, and there were two Dell Inspiron 8100’s at the end of the x-ray machine. Another guy and I were looking at both laptops trying to figure out which one was ours. The other guy noticed that one of the laptops didn’t have a floppy drive … and he knew that his did have a floppy (mine had a spare 2nd battery). Just to be on the safe side, he booted his up and determined that the one he had was indeed his own. We laughed about it briefly and went to our respective flights.
An acquaintance of mine wasn’t so lucky once … he was on a business trip to Europe … he went through security, grabbed the first laptop that looked like his, and headed over to his flight … but it turns out the laptop he grabbed wasn’t his. When he was on the plane, already over open ocean, he booted his laptop up and tried to login … but couldn’t. Then he noticed it wasn’t his name on the Windows XP login box. Talk about a panic. He ended up having to buy a new laptop at his destination, and getting his reference material sent to him via overnight shipment.
Want a proof positive way to avoid this kind of problem? Take your business card and tape it to the inside of your removable battery (or the bottom of a removable CD/DVD drive).
It’s important that the business card be taped … so it doesn’t fall off and it’s clear that it couldn’t have just been slipped there.
It’s also not a bad idea to put something identifiable on the outside of the case, so you know you’re grabbing the right laptop. This could be something as simple as a piece of colored tape.
Now, if there is ever confusion about who owns a laptop, you just pop out the battery and you can quickly determine which laptop is yours.
Thunderbird message list out of sync
Sometimes I find that the message list in Thunderbird gets out of sync with the message bodies. When this happens, if I click on a message in the list, the message body that is brought up doesn’t match the subject.
I found a easy solution … just shut down Thunderbird, delete the corresponding .msf file from the accounts data directory, and start Thunderbird back up. Thunderbird will rebuild the .msf file and everything should be fine again.
To find accounts data directory, click on the “Server Settings” category of the effected account and look at the “Local directory” field.
[tags]thunderbird, mozilla, email[/tags]
DST
Spring forward and fall back.
Don’t forget to set your clocks ahead one hour (like I have on more than one occasion).
I’m off to change the clocks RIGHT NOW.