If you enable it, which used to be the norm, you may get blacklisted for BACKSCATTER.
Here are the settings we use to minimize the sending of messages and responses, thus lowering any possibility we might be accused of "backscatter" and placed on an RBL list:
Additional protective settings, including more information on backscatter, along with other helpful information on ensuring delivery of e-mail which originates on your SmarterMail MX server, can be found in the following two documents I have published:
Bruce Barnes
Bruce Barnes
ChicagoNetTech Inc
brucecnt@comcast.net
Phonr: (773) 491-9019
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting