EmailFilter filters input records according to a specified condition.
|Component||Same input metadata||Sorted inputs||Inputs||Outputs||Java||CTL||Auto-propagated metadata|
|Input||0||For input data records||Any|
|Output||0||For valid data records||Input 0|
|1||For rejected data records||Any|
 Metadata on the output port 0 contain any of the input data fields plus up to two additional fields. Fields whose names are the same as those in the input metadata are filled in with input values of these fields.
Metadata cannot be propagated through this component.
Metadata on the output port 0 contain any of the input data fields plus up to two additional fields. Fields whose names are the same as those in the input metadata are filled in with input values of these fields.
Table 62.3. Error Fields for EmailFilter
|Field number||Field name||Data type||Description|
|FieldA||the Error field attribute value||string||Error field|
|FieldB||the Status field attribute value||integer||Status field|
 The following error codes are the most common:
A list of selected input field names whose values should be verified as valid or non-valid email addresses. Expressed as a sequence of field names separated by a colon, semicolon, or pipe.
|Level of inspection|
Various methods used for the email address verification can be specified. Each level includes and extends its predecessor(s) on the left. For more information, see Level of Inspection.
|SYNTAX | DOMAIN (default) | SMTP | MAIL|
By default, even an empty field is accepted as a valid address.
This can be switched off by setting to
|true (default) | false|
|Error field||The name of the output field to which an error message can be written (for rejected records only).|
|Status field||The name of the output field to which an error code can be written (for rejected records only).|
A regular expression that serves to split an individual field value to multiple email addresses. If empty, each field is treated as a single email address.
|[,;] (default) | other|
By default, a record is accepted even if at least one field value is verified as a valid email address.
If set to
|LENIENT (default) | STRICT|
|E-mail buffer size|
Maximum number of records that are read into memory after which they are bulk processed. For more information, see Buffer and Cache Size.
|2000 (default) | 1-N|
|E-mail cache size|
The maximum number of cached email address verification results. For more information, see Buffer and Cache Size.
|2000 (default) | 0 (caching is turned off) | 1-N|
|Domain cache size|
Maximum number of cached DNS query results.
Is ignored at
|3000 (default) | 0 (caching is turned off) | 1-N|
|Domain retry timeout (ms)|
The timeout in millisecond for each DNS query attempt. Thus, maximum time in milliseconds spent to resolving equals to Domain retry timeout multiplied by Domain retry count.
|800 (default) | 1-N|
|Domain retry count||The number of retries for failed DNS queries.||2 (default) | 1-N|
|Domain query A records|
By default, according to the SMTP standard,
if no MX record could be found, the A record should be searched.
If set to
|true (default) | false|
|SMTP connect attempts (ms,...)|
Attempts for connection and HELO. Expressed as a sequence of numbers separated by a comma. The numbers are delays between individual attempts to connect.
|SMTP anti-graylisting attempts (s,...)|
Anti-graylisting feature. Attempts and delays between individual attempts expressed as a sequence of number separated by a comma. If empty, anti-graylisting is turned off. For more information, see SMTP Gray-Listing Attempts.
|SMTP request timeout (s)||The TCP timeout in seconds after which a SMTP request fails.||300 (default) | 1-N|
|SMTP concurrent limit||The maximum number of parallel tasks when anti-graylisting is on.||10 (default) | 1-N|
|Mail From||The ||CloverDX <firstname.lastname@example.org> (default) | other|
|Mail Subject|| The ||Hello, this is a test message (default) | other|
|Mail Body||The |
Hello,\nThis is CloverDX text message.\n\nPlease ignore and don't respond. Thank you, have a nice day! (default) | other
EmailFilter receives incoming records through its input port and verifies specified fields for valid email addresses. Data records that are accepted as valid are sent out through the optional first output port, if connected. Specified fields from the rejected inputs can be sent out through the optional second output port, if it is connected to other component. Metadata on the optional second output port may also contain up to two additional fields with information about an error.
Increasing E-mail buffer size avoids unnecessary repeated queries to DNS system and SMTP servers by processing more records in a single query. On the other hand, increasing E-mail cache size might produce even better performance since addresses stored in cache can be verified in an instant. However, both parameters require extra memory so set it to the largest values you can afford on your system.
By default, even an empty field from input data records
specified in the List of fields is considered to be a valid email address.
The Accept empty attribute is set to
true by default.
If you want to be more strict, you can switch this attribute to
In other words, this means that at least one valid email address is sufficient for considering the record accepted.
On the other hand, in case of Accept condition set to
all email addresses in the List of fields must be valid
(either including or excluding empty values depending on the Accept empty attribute).
Thus, be careful when setting these two attributes:
Accept empty and Accept condition.
If there is an empty field among fields specified in List of fields,
and all other non-empty values are verified as invalid addresses,
such record gets accepted if both Accept condition is set to
and Accept empty is set to
However, in reality, such record does not contain any useful and valid email address,
it contains only an empty string which assures that such record is accepted.
At the first level of validation (
the syntax of email expressions is checked and even both non-strict conditions
and international characters (except TLD) are allowed.
At the second level of validation (
DOMAIN) - which is the default one
a DNS system is queried for domain validity and mail exchange server information.
The following four attributes can be set to optimize the ratio of performance to false-negative responses:
Domain cache size, Domain retry timeout,
Domain retry count and Domain query A records.
The number of queries sent to a DNS server is specified by the Domain retry count attribute.
Its default value is 2.
The time interval between individual queries that are sent is defined by Domain retry timeout in milliseconds.
By default, it is set to 800 milliseconds.
Thus, the whole time during which the queries are being resolved is equal to
Domain retry count x Domain retry timeout.
The results of queries can be cached.
The number of cached results is defined by Domain cache size.
By default, 3,000 results are cached.
If you set this attribute to 0, you turn the caching off.
You can also decide whether A records should be searched,
if no MX record is found (Domain query A records).
By default, it is set to
Thus, A record is searched, if MX record is not found.
However, you can switch this off by setting the attribute to
This way you can speed the searching two times, although this breaks the SMTP standard.
At the third level of validation (
attempts are made to connect SMTP server.
You need to specify the number of attempts and time intervals between individual attempts.
This is defined using the SMTP connect attempts attribute.
This attribute is a sequence of integer numbers separated by commas.
Each number is the time (in seconds) between two attempts to connect the server.
Thus, the first number is the interval between the first and the second attempts,
the second number is the interval between the second and the third attempts, etc.
The default value is three attempts with time intervals between the first and the second attempts equal to
1,000 and between the second and the third attempts equal to 2,000 milliseconds.
Additionally, the EmailFilter component,
SMTP/MAIL test for specified number of times and delays.
Only after the last retry fails, the address is considered as invalid.
At the fourth level (
its subject is
Hello, this is a test message.
And its default body is as follows:
Hello,\nThis is CloverDX test
message.\n\nPlease ignore and don't respond. Thank you and have a
To turn the anti-graylisting feature, you can specify the SMTP gray-listing attempts attribute. Its default value is 30,120,240. These numbers means that four attempts can be made with time intervals between them that equal to 30 seconds (between the first and the second), 120 seconds (between the second and the third) and 240 seconds (between the third and the fourth). You can change the default values by any other comma separated sequence of integer numbers. The maximum number of parallel tasks that are performed when anti-graylisting is turned on is specified by the SMTP concurrent limit attribute. Its default value is 10.