I have a VPS that I have been using for a personal site with a webserver and mail server as public-facing services. All DNS records are set up and everything is fine.
*.mysite.com A 111.222.333.444
host.mysite.com. MX 111.222.333.444
blah444.333.222.111 PTR host.mysite.com
I am now going to host several virtual domains, and I want to avoid DNS information leakage.
To that end, I thought to change the PTR record to point to the machine's (newly changed) internal hostname instead of one of the domain's publicly resolvable host. From what I've read, upstream SMTP servers should accept email from the host as long as the PTR matches the hostname (i.e. it doesn't have to match up with a resolvable A record).
*.domainA.com A 111.222.333.444
*.domainA.com. MX 111.222.333.444
*.domainB.com A 111.222.333.444
*.domainB.com. MX 111.222.333.444
blah444.333.222.111 PTR host.myinternalserver.net
Apparently, this is the recommended way of handling virtual hosting (again, from what I've read elsewhere).
Any comments on the consequences? Also, will it affect other public services, which will be web server, vpn, ssh? The MTA is postfix, by the way.