I LOVE computer networking (it’s what I spent a big chunk of the last few years at work doing), but getting started with all the tools was originally a little tricky! For example – what if you have the IP address of a server and you want to make a https connection to it and check that it has a valid certificate? But you haven’t changed DNS to resolve to that server yet (because you don’t know if it works!) so you need to use the IP address? If you do
curl https://126.96.36.199/, curl will tell you that the certificate isn’t valid (because it’s not valid for 188.8.131.52). So you need to know to do
curl https://jvns.ca --resolve jvns.ca:443:184.108.40.206.
I know how to use
curl --resolve because my coworker told me how. And I learned that to find out when a cert expires you can do
openssl x509 -in YOURCERT.pem -text -noout the same way. So the goal with this zine is basically to be “your very helpful coworker who gives you tips about how to use networking tools” in case you don’t have that person.
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