Working with DNS whitelists for SMTP connections
Use DNS whitelist filters as a means to help identify legitimate email. When DNS whitelist filters are enabled, the SMTP listener task determines whether a connecting host is a member of a DNS whitelist by relying on the results of a DNS query of a DNS blacklist-style host name. If the query returns an IP address, the host is added to the whitelist and the remaining DNS whitelists are not searched. If the host is not found in the DNS whitelist , processing continues with DNS blacklist filters. If the query returns an error indicating that the host name is not valid, the host is not added to the whitelist and may be subject to blacklist filtering if that is enabled.
Before you begin
About this task
DNS whitelists can be used independently of blacklists but private blacklists override DNS whitelists.
Procedure
Viewing DNS whitelist statistics
About this task
The SMTP listener task maintains a statistic to keep a cumulative count of the number of connections accepted from DNS whitelisted hosts. The statistic, SMTP.DNSWL.TotalHits, can be viewed using the Domino Administrator client, or by issuing this command from the server console:
show stat SMTPTo determine the number of times a particular
IP address is listed in one of the configured DNS whitelists, expand
the SMTP.DNSWL.<WhitelistSite>.IP address.Hits
statistic.
To
collect the expanded information, set the NOTES.INI variable SMTPExpandDNSWLStats
=1
.