Create u_e-dovecot-sieve_filter.en.md

docs/manual-guides/Dovecot/u_e-dovecot-sieve_filter.en.md

@@ -0,0 +1,32 @@
+Here is just an example of Sieve rule.
+
+on your /mailbox, Tab "Filters".
+
+You can create "Add filter" and Select domain.tld and Prefilter.
+
+## Rule Example for matches To and redirect mail, mark as read and move mail on subfolder
+
+```
+require "fileinto";
+require "mailbox";
+require "variables";
+require "subaddress";
+require "envelope";
+require "duplicate";
+require "imap4flags";
+
+if header :matches "To" "*mail@domain.tld*" {
+   redirect "anothermail@anotherdomain.tld";
+   setflag "\\seen"; /* Mark mail as read */
+   fileInto "INBOX/SubFolder"; /* Move mail on subfolder after */
+} else {
+  # The rest goes into INBOX
+  # default is "implicit keep", we do it explicitly here
+  keep;
+}
+```
+Keep Warning about From/To : if on source of your mail, you see firstname name <mail@domain.tld> : Your "if header" need to match all data
+If you use ":is" to replace ":matches", you need to set the exact patern.
+
+[Examples rules Sieve](https://doc.dovecot.org/configuration_manual/sieve/examples/)
+[IETF : Draft with examples](https://datatracker.ietf.org/doc/html/draft-happel-sieve-filter-rule-metadata-00)