diff --git a/imap_filter/imap_filter.py b/imap_filter/imap_filter.py
index c9847bf..7b139d3 100644
--- a/imap_filter/imap_filter.py
+++ b/imap_filter/imap_filter.py
@@ -26,6 +26,14 @@ except ImportError:
 import click
 import click_config_file
 
+REQUIRED_MAILBOX_FIELDS = [
+    'mailbox',
+    'imap_user',
+    'imap_password_file',
+    'imap_server',
+    'imap_port',
+    'imap_ssl'
+]
 class ImapFilter:
     '''IMAP filter tool'''
 
@@ -46,6 +54,7 @@ class ImapFilter:
             )
         self._init_log()
         signal(SIGINT, self._signal_handler)
+        self.imap = None
         with open(self.config['filters_file'], 'r', encoding='UTF-8') as filters_file:
             self._log.debug(
                 "Reading filters file '%s'...",
@@ -67,7 +76,6 @@ class ImapFilter:
                 "Filters file is empty. Use --help to see more details."
             )
             sys.exit(1)
-        self.connect_imap()
         self._process_filters()
         self._log.debug(
             "Took %s seconds to process",
@@ -77,12 +85,21 @@ class ImapFilter:
     def _process_filters(self):
         matches = 0
         for mailbox in self.config['mailboxes']:
-            if 'mailbox' not in mailbox:
-                self._log.warning(
-                    "No mailbox name in %s, skipping.",
-                    mailbox
-                )
-                break
+            for field in REQUIRED_MAILBOX_FIELDS:
+                if field not in mailbox:
+                    self._log.warning(
+                        "Missing required field '%s' in mailbox '%s', skipping.",
+                        field,
+                        mailbox
+                    )
+                    break
+            self.connect_imap(
+                imap_server=mailbox['imap_server'],
+                imap_port=mailbox['imap_port'],
+                ssl=mailbox['imap_ssl'],
+                imap_user=mailbox['imap_user'],
+                imap_password_file=mailbox['imap_password_file'],
+            )
             if mailbox['mailbox'] == 'INBOX' and self.config['sieve_scripts_path']:
                 self._create_sieve_script(mailbox['filters'])
             else:
@@ -405,38 +422,44 @@ class ImapFilter:
             return False
         return True
 
-    def connect_imap(self):
+    def connect_imap(self, imap_server, imap_port, ssl, imap_user, imap_password_file):
         '''Create connection object to the IMAP server'''
         self._log.debug(
             'Connecting to server %s:%s...',
-            self.config['imap_server'],
-            self.config['imap_port']
+            imap_server,
+            imap_port,
         )
-        if self.config['ssl']:
+        if ssl:
             try:
-                self.imap = imaplib.IMAP4_SSL(self.config['imap_server'], self.config['imap_port'])
+                self.imap = imaplib.IMAP4_SSL(imap_server, imap_port)
             except Exception as error:
                 self._log.error(
                     "Error connecting securely to IMAP server '%s'. %s",
-                    self.config['imap_server'],
-                    error
+                    imap_server,
+                    error,
                 )
                 sys.exit(1)
         else:
             try:
-                self.imap = imaplib.IMAP4(self.config['imap_server'], self.config['imap_port'])
+                self.imap = imaplib.IMAP4(imap_server, imap_port)
             except Exception as error:
                 self._log.error(
                     "Error connecting to IMAP server '%s'. %s",
-                    self.config['imap_server'],
-                    error
+                    imap_server,
+                    error,
                 )
                 sys.exit(2)
+        with open(imap_password_file, 'r', encoding='utf-8') as pass_file:
+            imap_password = pass_file.read().trim()
         try:
-            self._log.debug('Authenticating as user %s...', self.config['imap_user'])
-            self.imap.login(self.config['imap_user'], self.config['imap_password'])
+            self._log.debug('Authenticating as user %s...', imap_user)
+            self.imap.login(imap_user, imap_password)
         except Exception as error:
-            self._log.error("Error while login as '%s'. %s'", self.config['imap_user'], error)
+            self._log.error(
+                "Error while login as '%s'. %s'",
+                imap_user,
+                error,
+            )
             self.imap.close()
             sys.exit(3)