![]() ![]() To turn on DNSBL for a specific IP, go to EMF webadmin > Setup > Relays > Network Connections, and set the DNSBL column to "Perform". The DNSBL check is a forward DNS (port 53) A-record lookup, and therefore an insignificant performance hit. Does DNSBL use a lot of system resources, in other words will we start seeing performance problems? to MAPS, separately from your EMF license. Do we have to subscribe to one of these services? We need to reiterate that Tumbleweed has not done any testing with the changing of this value, and you are on your own doing it, but we do not know of any reason why it wouldn't work.ģ. Please see the MAPS site for all relevant RBL Hostnames. (EMF 5.6 added a UI Set Up option called Configuration Editor, which can be used to modify the Rela圜onfigValues table see the EMF Admin Guide for more details.)įor example, if you wanted to use the RSS service from MAPS, you may change the value of 'RBL Hostname' to be ''. However, this value can be overridden by adding a row to the Rela圜onfigValues table within the EMFMail database, such that the column is RBL Hostname and the is. EMF uses a default value for the RBL Hostname of. The Zone (or RBL Hostname) for the RBL service is "". That said, according to MAPS all 4 services behave in exactly the same manner, and the only difference between the services is the "zone" as MAPS calls it, or the service Hostname (also called the "RBL Hostname"). (Please go to the MAPS site for descriptions of these services.) Although only RBL has been tested and is officially supported by Tumbleweed, we know, and have some customers successfully using RBL+, by making a one line change in the EMF database (see next paragraph for the change). MAPS offers at least 4 related services: RBL, RSS, DUL, and RBL+, which is a combination of the first 3. The mode you select (Query or Transfer) depends on how you wish to administer your DNS server, as discussed above. The default DNSBL site: Mail Abuse Prevention System LLC (MAPS), at, and the service we use is RBL. (NOTE: events 10 will include in the event details the IP being tested.)Ģ. Other DNSBL services have similar arrangements.Īfter obtaining your subscription from MAPS, you should have MAPS provide specific instructions to you to set up your DNS server for the query or transfer method.Įvent ID 1047 - Info / Trace - "DNSBL query"Įvent ID 1048 - Warning / Normal - "Host found on the blackhole list"Įvent ID 1049 - Info / Trace - "Host was not found on the blackhole list" In the "transfer mode", you would arrange a zone DNS transfer from MAPS, so that the domain information is available locally on your DNS server. In the "inquiry mode", you would configure your DNS server such that whenever a query is made on the DNSBL domain (), that query is forwarded (delegated) to a DNS server hosted by MAPS. These correspond to the inquiry (query) mode and transfer mode, using the terminology from the MAPS web site. There are two ways to make DNSBL information available in your DNS server from the MAPS site. (If the information is not available, no hosts will be blocked due to DNSBL membership. It is your responsibility to arrange it so that when the SMTP relay queries the DNS, the DNSBL information is available from that DNS server. EMF does not query a special DNS server for DNSBL information it uses the same DNS server(s) that you have configured your EMF SMTP relay services to use. The DNS server that is queried is the same one that your EMF relay service is configured to use for SMTP routing. If the host is found, it is considered to be on the black hole list. Spammers use open relays to send their spam.ĮMF performs a DNS query for a hostname, which is formed by taking the IP address of the suspect SMTP client (in reverse dotted quad order) and appending the DNSBL domain name, e.g., (MAPS).įor example, if EMF gets a connection from host 10.20.30.40 and the DNSBL check is enabled, EMF will perform an A-record DNS query, e.g., for host 40.30.20.10. on your DNS server. Your EMF server is having to process a large amount of spam email. The default site specified in the EMF webadmin is (MAPS).ĭNSBLs were formerly known as RBLs (Realtime Blackhole Lists) in previous versions of EMF. The lists of open relays are called DNS "blackhole lists", maintained by several subscription sites on the Internet. EMF has the capability to check each incoming network connection against publicly-available lists of open relay sites (servers), and refuse connection if the connecting site is on the list.
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