======Spam Filter Rules: DNSBL======
^Statement  |DNSBL |
^Version  |2.1.7+ |
^Purpose  |Allows the script to perform a DNS blacklist lookup, returning the result into a specified variable |

The **DNSBL** statement requires a hostname, DNSBL zone and variable name, in the format
  DNSBL <hostname> <DNSBL zone> <variable name>

**See also**
  * [[spamrules_statement_startdnsbl|StartDNSBL]] - Can be used in advance of **DNSBL** being called, to improve script efficiency

=====Example=====
The following example returns the result of the DNS blacklist lookup into the ${dnsresult} variable, then compares that to a value and, if it matches, logs the result and adds onto the spam filter score.

<code>
DNSBL ${SenderIP} sbl.spamhaus.org dnsresult
IfMatch ${dnsresult} "/^127\.0\.0\.2$/"
  Log "(${SenderIP}) found in SBL.Spamhaus (${dnsresult})"
  ${Score} += 100 [sbl.spamhaus.org]
EndIf
</code>