Question about "Perform reverse DNS lookup on incomin..

Dear all,



I install a IIS 6 SMTP for my SMTP gateway, and them relay emails to my
Exchange server. Yesterday I enable ¡§Perform reverse DNS lookup on incoming
messages¡¨, but looks like some customer¡¦s email can¡¦t send to our
company.



I have some problem need your help:

1. Should I enable this function?

2. Where can I check the reverse DNS lookup log? Such as what kind of
was accept and what kind of domain name was reject?

3. Will IIS SMTP archive the reject emails?



Many thanks for you help!