Using a zonefile to find all servers using a wildcard SSL certificate
I recently had to renew a wildcard SSL certificate. The certificate is being used on a couple of servers and I was too lazy to look through all of my Ansible repositories to find out where.
A friend had the idea to use the zone file for that domain. I pulled the zonefile, stripped it down to the subdomains (removing all other record information), de-duplicated and sorted it.
Now I got a long list of subdomains/strings. A simple loop connects to all domains using openssl and prints an error or the certificate dates.
for i in (cat zonefile) echo $i echo \ | openssl s_client -connect $i.<DOMAIN>:443 2> /dev/null \ | openssl x509 -noout -dates end
So I knew which server is using the wildcard certificate and which was about to expire.
Maybe I should start working on a central SSL termination…