Is it OK to use my public domain name as my internal AD domain name instead of using .local internally?

I am taking over a project and the local domain name is domain.com; they also have a website at domain.com.

I have always used domain.local for AD, and am wondering if that is a best practice or is there a reason for not doing so.

Running an nslookup internal for domain.com does resolve to the proper IP and the rDNS records are configured correctly.

I would like to start connecting some of the servers and the vCSA through LDAP, and am wondering if this might start causing problems?

our internal domain is a sub-domain of our public domain. we use split dns as well as some of our websites etc which are publicly available are internal and have to resolve to different ip addresses internally as opposed to externally.

you can get away with using your domain internally, as said above. you just have to get your head around the split dns