Page updated 1 November 2012
Introducing
Filters
Filters allow automatic management of messages received from the server. Certain actions can be invoked on messages that match user-defined conditions, usually based on the content of header lines. They can be used for such things, marking spam for deletion and sorting mail into different Saveboxes according to sender or subject.
A Filter tab exists on both the Global Options, where the dialogue controls filters to be applied to all accounts, and the Account Settings dialogue where filters are applied to the selected account only.
Any number of filter items may be added to an account's settings. As each message is retrieved it is checked against the first filter. If the conditions for the first filter are met, its action is executed. If the conditions fail then the following filter is checked and so on. Certain filter actions (e.g. Accept and Reject) stop any further filters in the list from being checked. Others limit the validity of certain following filters, If a message fails to meet the conditions for all the filters then the message will be accepted subject to the settings under the RECV tab of the Global Options dialogue.
Filter
Dialogue Controls
The majority of the Filter dialogue controls are initially inactive.
- Enable filters
- Must be checked for any filter actions to take place. Once enabled further options and buttons are activated.
- Refilter on download (Only on Account Settings)
- If checked, filters will be applied when the server is updated to download fully a partially retrieved message.
- Use globals (Only on Account Settings)
- The box is active only if global filters, available to be applied to all accounts, have been defined. If checked, the global filters will be applied to this account before those for the selected account.
- Up/Down Arrow
- These buttons become active when filters have been defined. Individual filter rules may be moved up and down the list with the buttons to the right of the list. Because filters are applied in order, it is important to place "exceptional" filters higher than those to be more generally applied (see Examples).
- Add
- Opens the "Filter Item" dialogue used to construct a new filter.
- Edit
- Reopens the Filter Item dialogue for the selected filter.
- Delete
- Deletes the selected filter permanently.
- OK
- Confirms all filter details and writes them to the nPOPuk.ini file
- Cancel
- Aborts the current filter editing session.
Filter Rules
For a filter item to execute an action either one or two conditions must be true. If a second condition is set then an appropriate radio button must also be selected to relate the two conditions.
Actions
The possible filter actions are:
- Reject
- nPOPuk will reject the message, discarding any received portion of a message that meets the conditions given. (When messages are rejected, the Status Line will indicate an increased number of Server items not reflected in the View items.) This action also stops nPOPuk from checking any remaining filters from the account.
- Accept
- The message will be accepted: it is added to the Mailbox and shown in the message list. This action also stops nPOPuk from checking any remaining filters from the account.
- Mark to download
- nPOPuk will mark the message for full download at the next server update. Once marked for download, a message cannot be marked for deletion by a subsequent filter.
- Mark to delete
- nPOPuk will mark the message for deletion at the next server update. Once marked for deletion, a message cannot be marked for download by a subsequent filter.
- Mark as read
- nPOPuk will mark the message as read.
- Copy to:
- nPOPuk will copy the received portion of the message to the Savebox
selected from the drop-down list that is activated on selecting this
action.
NOTE: Depending on the Global Options, nPOPuk may not initially receive the entire message. Only the received portion of the message is copied to the Savebox. - Move to:
- nPOPuk will both mark the message for deletion at the next server
update and copy it to the Savebox selected from the drop-down list
that is activated on selecting this action.. Once the filter action
"move to" is applied to a message, the message cannot be copied to
another Savebox by any subsequent filter.
CAUTION: Using this filter causes the original message to be marked to delete. Attachments and the text of long messages may be lost unless nPOPuk is set to Download entire body when checking. - Set Priority:
- nPOPuk will mark the message with one of the following three indicators: Flag, High Priority or Low Priority, or will remove a High or Low Priority indicator (i.e. set Normal). The markers are selected from the drop-down list that is activated on selecting this action.
- Forward to:
- nPOPuk will place a copy of the message in the Outbox, marked to
send to the address entered in the field that becomes activated on
selecting this action.
NOTE: The forwarded message is not sent until the next server update.
Items
The filter conditions are based on e-mail header lines. These specify not only the address of the sender, subject line, and date and time of the message, but also routing information (to allow undelivered messages to be returned to the sender) and other technical information, e.g. the program used to create the e-mail.
One or two headers in any message may be checked by an individual rule for particular conditions. In the dialogue the headers to be tested are labelled "Item1:" and "Item2:" and the two conditions.may be applied with the boolean operators AND (both conditions must be true), OR (either condition can be true) or AND NOT (Labelled as "UNLESS", i.e. Item 1 must be true, unless Item 2 is true).
Any header line may be tested by typing it into the "Item1" or "Item2" line, but the following may be selected from the drop-down list and do not need to be typed:
| From: | To: | Cc: | Subject: |
| Organization: | Reply-To: | Comments: | Content-Type: |
| Date: | Keywords: | Sender: | X-Mailer: |
| X-Priority: | X-Sender: | X-ML-Name: |
Content
Except for the special cases mentioned below, "Content1" and "Content2:" must match exactly the content of the given header line in the source of the e-mail, including capitalisation, punctuation and spacing. In order to ascertain the true contents of header lines it may be necessary to turn on the Include header lines feature, as sometimes the information shown in the headers nPOPuk displays is NOT identical to the true header in the message source.
Wildcard:
A * symbol may be used as a wild card to represent any number of additional characters. This is particularly useful for addresses and popular words used as subject lines by spammers. For example, addresses can appear in e-mail header lines with the "real" name added (with or without quotes) and the address may be enclosed in less/greater than <symbols>.
NOTE: In almost all cases the use of twin wildcards wrapping the content text will be required, as shown in the default sample entry "*v1agra*".
From:
Where "From:" is selected as the item one of two special Content entries may be used. (Be aware that both these content items can degrade performance if the address book is large, particularly if entries have multiple groups as the program has to split the string and check each one):
**INADDRESSBOOK
When this is entered the filter will trap any address in nPOPuk's
Address Book.
**INGROUP groupname
When this is entered and where "groupname" represents the name of a
group in your address book the filter will trap addresses that are
included in that group.
Date:
Where "Date:" is selected as the item one of two special Content entries may be used:
**OLDERTHAN n
**NEWERTHAN n
When one of these are entered and where "n" is a number representing the
number of days, the filter will trap mail that is older or more recent
than the given number of days.
Examples
To delete any mail from a Hotmail address when the server is next
updated:
NOTE: As it is difficult to
predict the exact format of the address line the crucial portion of
the address is wrapped in wildcards.
| Action | Item 1 | Content 1 |
|---|---|---|
| Mark to delete | From: | *@hotmail.com* |
To delete spam offering you business proposals:
| Action | Item 1 | Content 1 |
|---|---|---|
| Mark to delete | Subject: | *PROPOSAL* |
To accept mail only from those with an address stored in your address book:
| Action | Item 1 | Content 1 | Condition | Item 2 | Content 2 |
|---|---|---|---|---|---|
| Reject | From: | * | UNLESS | From: | **INADDRESSBOOK |
Assuming that you have the default setting to download only 100 lines of any mail, then the following filter could be used to accept large attachments only from those known to you:
| Action | Item 1 | Content 1 |
|---|---|---|
| Mark to download | From: | **INADDRESSBOOK |
Two ways to retrieve only mail dated within the last fortnight:
NOTE: Version two highlights the
fact that if you have no filters messages will be accepted. So if you
just use an "accept recent mail" rule, then mail that doesn't match the
rule passes through the filter, so you need the second "reject all mail"
rule to stop everything else.
| Action | Item 1 | Content 1 |
|---|---|---|
| Reject | Date: | **OLDERTHAN 14 |
OR
| Action | Item 1 | Content 1 |
|---|---|---|
| Accept | Date: | **NEWERTHAN 14 |
| Reject | Date: | * |
The following set of filters could appear on a computer at home and
must appear in this order to be effective.
1. Messages from your employer will be accepted and copied to your
"Work" Savebox (so you can answer them from home, but still have them
available to download at work).
2. Mail that fails the first test will be checked with your address
book, marked for deletion, and copied to your "Home" Savebox.
3. Mail that fails the first two tests will be treated as spam and
marked to be deleted.
NOTE: The importance of this
order of filter items is based on the assumption that the employer's
address will be in the address book, so the rule to copy employer's mail
must be executed before the move filter, which would delete such mail
and make it unavailable at work to be downloaded from the server.
| Action | Savebox | Item 1 | Content 1 |
|---|---|---|---|
| Copy to: | Work | From: | *@myemployer.com* |
| Move to: | Home | From: | **INADDRESSBOOK |
| Mark to delete | To: | From: | * |