Question : How do reverse DNS entries get reset?

I've had it happen to a client of mine and here at my office in the past two weeks.  One was with Comcast, mine is with SpeakEasy.  I called and had them set up a custom rDNS and it worked well.  Then, my client called saying they were going to people's spam folders.  Looked into it and the rDNS was some generic Comcast entry (64-38-19-67.hsd1.wa.comcast.net or something).  Called Comcast and they set it back up and I haven't heard a complaint since.

This is the first time in my 3 years of server/network experience that I've ever seen this happen.  Anyone know why?

Answer : How do reverse DNS entries get reset?

This is a fault at the ISP end, If they provide a static IP address, and have set up a PTR record for you, it should not be returned to PTR placeholder by the ISP. Bad admin. Complain. I haven't seen this happen before.

Shaun