Implications of hosting CNAMES and A records on separate name servers

Question

We host several websites but in most cases the client hosts their own DNS and mail separately.

I want to set up a system where we will create a subdomain on our domain for each client site which will act as the clients A record, so we can control the IP.

For example on the clients name server for domain clientwebsite.com set up:

@    CNAME clientwebsite.sharedhostingenv.com
www  CNAME clientwebsite.sharedhostingevn.com

And on our name servers create the subdomain on sharedhostingenv.com:

clientwebsite IN A 222.33.55.66

Will the fact that the client no longer hosts their own A record have any effect on any other records they have? Will this adversely affect any MX records that the client hosts?

edit: Thank you for the feedback!!! I can't comment, but cheers.

Answer 1

Don't do this:

@    CNAME clientwebsite.sharedhostingenv.com

That will break all other resource records for your clients domain. See this Q&A for a long explanation.

Second when using FQDN's in DNS zones, do not omit the trailing . dot.
In DNS shorthand an entry such as clientwebsite.sharedhostingevn.com in your client's example.com. DNS zone effectively becomes: clientwebsite.sharedhostingevn.com.example.com.