We are going to deploy a centralized authentication Linux server (RHEL6) for our RedHat/CentOS servers in Data Center environment. I made some search I believe Free IPA is the best choice since it's more secure, it has better sudo and HBAC rules, ability to set password polices, it can be integrated with Windows Active Directory, and others.
However, I have issue with NTP and DNS, we already have our DNS and NTP clusters in DC environment. I believe I can make IPA as DNS forwarder, but it will still a middleware. Moreover, we are not going to have the IPA server as cluster, so it would be risky somehow to be a centralized DNS and NTP server.
My questions here: 1. Why should I have DNS & NTP are centralized from IPA? 2. Can I avoid configuring DNS & NTP and satisfy by my existing DNS & NTP servers for my IPA clients? Also, avoid to have IPA as a middleware for DNS & NTP? 3. Is there a better alternative than IPA, stable, scalable and easy configuration server?