How does DNS-01 validation for LetsEncrypt know what the right IP address is?

For my personal use, I bought a domain for internal ssl validation for my pfsense. I was able to get the LetsEncrypt’s ACME script to successfully validate my domain and produce an ssl certificate for a subdomain. I setup my pfsense to use… Continue reading How does DNS-01 validation for LetsEncrypt know what the right IP address is?

Does subdomain DNS cache poisoning depend on the authoritative name server ignoring requests for non-existing domains?

I’m reading "Introduction to Computer Security", Pearson New International Edition, 1st edition, by Goodrich and Tamassia.
On the subject of DNS cache poisoning, they mention that a "new" attack was discovered in 2008, … Continue reading Does subdomain DNS cache poisoning depend on the authoritative name server ignoring requests for non-existing domains?

Can I buy a standard SSL certificate to protect a website i.e. certificates.xxxxxx.com? [closed]

I don’t have much experience in buying and installing ssl certificates.
I have one website like certificates.xxxxx.com. So, my question is that can I buy a standard ssl certificate from GoDaddy to protect this one website.
xxxxx.com itself… Continue reading Can I buy a standard SSL certificate to protect a website i.e. certificates.xxxxxx.com? [closed]