- Antispam – rDNS and NDR block
The NDR Protection (Vbounce flag) was already available in the Protector. The rDNS option has been added with this firmware. Both these options now have in common the features to block email messages when these flags have been raised by the Anti-Spam filter. rDNS (reverse DNS lookup) is the process of resolving an IP address to its designated domain name. When a sending server makes a connection to the recipient server, the Protector performs a reverse DNS lookup (also called a PTR lookup). If the result doesn't match that of a forward lookup, it's likely that the sending address was spoofed and the mail message will be marked as “bad rDNS”. Being marked as such doesn’t necessarily mean that the mail will be blocked, as this action is usually taken by the Mail Servers. The Protector now allows to block all mail messages marked as bad rDNS or bad NDR by simply enabling the corresponding option in the Anti Spam Setup page.