DNS Filter
This filter will resolve any IP addresses from a field of your choosing.
The DNS filter performs a lookup (either an A record/CNAME record lookup or a reverse lookup at the PTR record) on records specified under the “reverse” and “resolve” arrays.
The config should look like this:
filter {
dns {
type => 'type'
reverse => [ "source_host", "field_with_address" ]
resolve => [ "field_with_fqdn" ]
action => "replace"
}
}
Caveats: at the moment, there’s no way to tune the timeout with the ‘resolv’ core library. It does seem to be fixed in here:
http://redmine.ruby-lang.org/issues/5100
but isn’t currently in JRuby.
filter {
dns {
action => ... # string, one of ["append", "replace"] (optional), default: "append"
add_field => ... # hash (optional), default: {}
add_tag => ... # array (optional), default: []
nameserver => ... # string (optional)
remove_field => ... # array (optional), default: []
remove_tag => ... # array (optional), default: []
resolve => ... # array (optional)
reverse => ... # array (optional)
timeout => ... # number (optional), default: 2
}
}
Determine what action to do: append or replace the values in the fields specified under “reverse” and “resolve.”
If this filter is successful, add any arbitrary fields to this event. Field names can be dynamic and include parts of the event using the %{field} Example:
filter {
dns {
add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
}
}
# You can also add multiple fields at once:
filter {
dns {
add_field => {
"foo_%{somefield}" => "Hello world, from %{host}"
"new_field" => "new_static_value"
}
}
}
If the event has field “somefield” == “hello” this filter, on success, would add field “foo_hello” if it is present, with the value above and the %{host} piece replaced with that value from the event. The second example would also add a hardcoded field.
If this filter is successful, add arbitrary tags to the event. Tags can be dynamic and include parts of the event using the %{field} syntax. Example:
filter {
dns {
add_tag => [ "foo_%{somefield}" ]
}
}
# You can also add multiple tags at once:
filter {
dns {
add_tag => [ "foo_%{somefield}", "taggedy_tag"]
}
}
If the event has field “somefield” == “hello” this filter, on success, would add a tag “foo_hello” (and the second example would of course add a “taggedy_tag” tag).
Only handle events without all/any (controlled by exclude_any config option) of these tags. Optional.
Use custom nameserver.
If this filter is successful, remove arbitrary fields from this event. Fields names can be dynamic and include parts of the event using the %{field} Example:
filter {
dns {
remove_field => [ "foo_%{somefield}" ]
}
}
# You can also remove multiple fields at once:
filter {
dns {
remove_field => [ "foo_%{somefield}" "my_extraneous_field" ]
}
}
If the event has field “somefield” == “hello” this filter, on success, would remove the field with name “foo_hello” if it is present. The second example would remove an additional, non-dynamic field.
If this filter is successful, remove arbitrary tags from the event. Tags can be dynamic and include parts of the event using the %{field} syntax. Example:
filter {
dns {
remove_tag => [ "foo_%{somefield}" ]
}
}
# You can also remove multiple tags at once:
filter {
dns {
remove_tag => [ "foo_%{somefield}", "sad_unwanted_tag"]
}
}
If the event has field “somefield” == “hello” this filter, on success, would remove the tag “foo_hello” if it is present. The second example would remove a sad, unwanted tag as well.
Forward resolve one or more fields.
Reverse resolve one or more fields.
Only handle events with all/any (controlled by include_any config option) of these tags. Optional.
TODO(sissel): make ‘action’ required? This was always the intent, but it due to a typo it was never enforced. Thus the default behavior in past versions was ‘append’ by accident. resolv calls will be wrapped in a timeout instance
Note that all of the specified routing options (type,tags.exclude_tags,include_fields,exclude_fields) must be met in order for the event to be handled by the filter. The type to act on. If a type is given, then this filter will only act on messages with the same type. See any input plugin’s “type” attribute for more. Optional.