I needed to see why an email script on an ec2 instance wasn't sending ~urgently~ (I didn't have any reception (tHaNks SpRiNt) otherwise I'd've hotspott'd and I couldn't go home) alas, Starbucks.
After ordering an unspeakable drink I sat betwixt the author of the next great American novella & a veritable hyena-y group of high-schoolers.
ssh: connect to host ec2-69-666-69-666.compute-1.amazonaws.com port 22: Connection refused
This = the ssh server process which listens to incoming connections which r using the ssh protocol. This lil binary is located at
/usr/sbin/sshd & starts on boot.
It enables things like tunneling, term connections, encryption. A cute way to test this that literally boggled my mind at first is
ssh localhost: your prompt changes, the files stay the same, bc.. they are. Explaining localhost (loopback/local... host) is kind of like writing a recursive function and je refuse.
Anyway, that worked.
& sipped my abomination.
d. a communication endpoint (not helpful)
d. in an OS, a port is a Logical Construct (don't click that link if you want to avoid spiraling down your own rabbit hole of truly titillating content re: Logical Constructions) (<plato.stanford.edu> is an amazing site).. starting over.
d. in an OS, a port is a designator for a specific process or a type of network service (not bad!)
voilà: a rabid fan base of sys admin-dom and Starbucks!
The ultimate culprit: Google, Google Fiber.
Found out I am also 5 years late to Breaking This Story lol, as the article above was published in 2014 😛.
Any who, it turns out that ISPs (Google in this case) can block traffic on specific ports. The gall.
At the time of writing (10 mins after it was posted, and curiously upvoted immediately) there is a lone comment:
A lively discussion has begun on my question, w/ two epic -1 answers (hopefully the downvoter(s) are busy writing rebuttals / The Answer):