Check IPs within 'Received' headers on SMTP delivered mail
Click this switch if you want DNS Block Lists to check the IP address stamped in the "Received" headers of messages received via SMTP.
Check only this many 'Received' headers (0 = all)
Specify the number of "Received" headers that you want DNS-BL to check, starting with the most recent. A value of "0" means that all "Received" headers will be checked.
Skip this many of the most recent 'Received' headers (0 =none)
Use this option if you want DNS-BL to skip over one or more of the most recent Received headers when checking SMTP messages.
Skip this many of the oldest ‘Received’ headers (0 =none)
Use this option if you want DNS-BL to skip over one or more of oldest Received headers when checking SMTP messages.
Check IPs within 'Received' headers on POP3 collected mail
When this switch is enabled DNS-BL will check the IP address stamped in the "Received" headers of messages collected via DomainPOP and MultiPOP.
Check only this many 'Received' headers (0 = all)
Specify the number of 'Received' headers that you want DNS-BL to check, starting with the most recent. A value of "0" means that all 'Received' headers will be checked.
Skip this many of the most recent 'Received' headers (0 =none)
Use this option if you want DNS-BL to skip over one or more of the most recent Received headers when checking DomainPOP and MultiPOP messages. Since it is often necessary to skip the most recent Received header on POP3 collected mail such as DomainPOP, this option has a default setting of "1".
Skip this many of the oldest ‘Received’ headers (0 =none)
Use this option if you want DNS-BL to skip over one or more of the oldest Received headers when checking DomainPOP and MultiPOP messages.
Settings
DNS-BL match adds this many points to the spam score
Use this option to specify a value that will be added to a message's spam score when a DNS-BL match is found. Sometimes the Spam Filter's heuristic examination of a message may not score it high enough to be considered spam, but a DNS-BL lookup may indicate that it is. Thus adding this value to the spam score could help catch some spam messages that might otherwise slip through undetected. By default a DNS-BL match adds 3.0 points to the spam score.
Don't check DNS-BLs if session is...
authenticated
Click this checkbox if you want those sessions that were authenticated using the AUTH command to be exempt from DNS-BL queries.
from a trusted IPs
Click this checkbox if you want addresses that are listed on the Trusted Hosts screen to be exempt from DNS-BL queries.
an ATRN dequeue
Enable this option if you do not wish to do DNS-BL lookups on mail collected over ATRN dequeue sessions. This setting is disabled by default but you can enable it if, for example, your smart-host is already doing DNS-BL checks on your stored mail..
Skip 'Received' headers within messages from IPs on the allow list
When this option is enabled, DNS-BL will not check the "Received" headers within messages coming from IP addresses that you have listed on the DNS-BL Allow List.
Stop further DNS-BL queries on first DNS-BL match
Oftentimes there are multiple hosts contained in the headers of each message that DNS-BL processes, and multiple DNS-BL services that are queried. By default, DNS-BL will continue to query these services for all hosts in the message regardless of the number of matches found. Click this option if you want DNS-BL to stop querying the services for any given message as soon as a match is found.
SMTP server should refuse mail from block-listed IPs
By default this box is unchecked, meaning that messages from block-listed IP addresses will not be refused during the SMTP session, but will have an X-MDDNSBL-Result header inserted. You can then use the Content Filter to search for messages with this header and do with them as you please. You can also use the "Auto-filter block-listed mail into user's spam folder" option below to filter messages automatically into each user's spam folder. Check this box if you wish MDaemon to refuse messages from block-listed IP addresses rather than flag them.
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Because some IP addresses can be block-listed by mistake, you should exercise caution before choosing to refuse messages rather than simply flagging them. It is also worth noting that in addition to flagging a message, you can adjust its spam score based on the DNS-BL results via the DNS-BL match adds this many points to the spam score option located on the Spam Filter. |
...and respond with 'Message' rather than 'user unknown'
Click this option if you want the specific Message you have assigned to the DNS-BL Host to be passed during the SMTP session whenever an IP address is found to be listed. Otherwise, a "user unknown" message will be passed instead. This option is only available if you have elected to use the "SMTP server should refuse mail from block-listed IPs" option above.
Auto-filter block-listed mail into user's spam folder
Click this option and a "Junk E-mail" IMAP folder will be created for all future user accounts that you add to MDaemon. MDaemon will also create a mail filter for each of those users, which will search for the X-MDDNSBL-Result header and then place messages containing that header into the user's spam folder. When you click this option you will also be asked whether or not you would like MDaemon to create this folder and filter for each of your already existing user accounts. See Auto-generating a Spam Folder and Filter for Each Account below.
Auto-generating a Spam Folder and Filter for Each Account
MDaemon can automatically create a "Junk E-mail" IMAP mail folder for each account and generate a mail filter that will move messages into that folder whenever it finds the X-MDDNSBL-Result header. Whenever you click the Auto-filter block-listed mail into user's spam folder option, you will be presented with the option to create the folder and accompanying filter for all accounts. Simply choose “yes” on the dialog to create the folders and filters. Although not foolproof, this is an easy and generally reliable way to help your users quickly identify spam email messages—it can effectively prevent spam email from being mixed in with all of their legitimate email. They will only occasionally need to review the contents of their spam folder just to make sure that an important message doesn't accidentally get put there (which may sometimes occur). When creating the folders and filters for your accounts, if MDaemon finds that an account already has a filter that checks for the existence of the X-MDDNSBL-Result header then no action will be taken and no filter will be created for that account. If you want the name of the IMAP folder to be something other than "Junk E-mail", you can change the default setting by editing the Default spam folder name option located on the System screen under Setup » Preferences.
