fun situations can arise when you write , instead of ; For those not in the know, in c++ the comma operator evaluates the left expression, discards the value, then evaluates the right expression and returns the value. if you now have a a situation like this
int i = 0,
printf("some message");
i has a completely different value, since it actually uses the return value of printf instead
You can use a DNS challenge to show you are in control of the domain without having anything exposed to the net. Essentially LE gives you a special value you have to add as a TXT DNS entry. LE will check if this record exists for your domain, and gives you a certificate, no public IP involved. This even allows you to create wildcard certificates.