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Only needs to be public for the challenge though. We use split DNS with an external server that has an empty zone. Internal clients are limited to setting their
by zeeZ 8y ago
Only needs to be public for the challenge though. We use split DNS with an external server that has an empty zone. Internal clients are limited to setting their respective _acme-challenge.subdomain TXT record and delete it afterwards.
- someone13 8y agoOut of curiosity, how is this implemented?
- w7 8y agoNot the person you asked, but: Besides possibly being a function of a provider's API; DNS server security policies can be used to limit updates to certain domains and/or record types based on preshared key. Since the DNS-01 challenge only needs to make a TXT record with a predetermined name you can configure a zone like so (using BIND syntax as an example): key "example-key" { algorithm hmac-sha512; secret <KEY_HERE>; }; zone { ... update-policy { grant "example-key" name _acme-challenge.example.com TXT; }; }; another option is to have a CNAME from _acme-challenge.example.com to a dedicated challenge zone like challenges.example.com that has similar restrictions. This coupled with something like acme.sh makes it easy and relatively secure for machines to generate their own certificates.