ISPConfig3 and sftdyn implementation

ISPConfig remote API is probably the way to go. See examples in remote_client folder of ISPConfig tar.gz file.

 

Another solution that I would propose if you're up for the task is to implement DNAME records in ISPConfig, so the functionality is available for all, and for other use cases. If unfamiliar, they are a pseudo record type similar to a CNAME, where a hostname (like your client website name) points to another name (such as your sftdyn hostname) and the DNS server infrastructure performs periodic DNS lookups for the latter name and updates DNS A records for the former name when the address changes.

DNAME is nice because it can work for the domain name itself, where CNAMEs usually can't be used, and has other uses (iirc, one more of cloudflare domain authentication was very simple with DNAME records).

 

Nice, did not hear of DNAME records before I'll add a feature request for adding them.

 

Following up on this, I made a mistake in calling these a DNAME record, that is something else (somewhat related, but different) - the correct term is ANAME.

I thought these were completely a non-standard and custom feature of various dns providers (and that is probably true), but it looks like there was at least one internet-draft specifying how these would be handled right in dns servers (https://tools.ietf.org/id/draft-ietf-dnsop-aname-01.html). Neither BIND nor PowerDNS appear to support ANAME; it looks like PowerDNS does support ALIAS in newer versions.

If ANAME were to be implemented in ISPConfig, https://www.quora.com/How-do-ANAME-records-work is interesting (particularly David Lawrence's comment, noting their refresh time for lookup is based on dns record expiration time).