Question : PTR record

I have some problems with my email account. Some people try send me email´s but the mail server (smartermail) refuse the email due spam. My isp tell me the sender have no PTR record. What is the PTR record in first place, and i can do any configuration to solve this problem.

Answer : PTR record

Read this on PTR, http://aplawrence.com/Blog/B961.html
But basically because of teh huge maount of spam nowadays most email servers require a reverse DNS check. mail from a legitimate source normally comes from a SMTP server which has a STATIC IP address the email part of your DNS consists of two parts the mx record, the name i.e mail.microsft.com  and an A record that points the IP address to mail.microsft.com
Many email servers will now reject email if the rDNS and and the MX record don't match. or if there is no mx record.

Basically email servers should be setup correctly.

As to is there anything you can do, ot really other than get whoever is sending you the email to get their email server setup correctly.