1 files changed, 6 insertions, 0 deletions
diff --git a/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php b/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
index ce6bc384c..a09f456e6 100644
--- a/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
+++ b/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
@@ -184,8 +184,14 @@ class rcube_sieve_engine
 
         list($host, $scheme, $port) = rcube_utils::parse_host_uri($plugin['host']);
 
+        // Support explicit STARTTLS by establishing an unencrypted TCP connection, then instructing Net_Sieve to send the `STARTTLS` command.
         $tls = $scheme === 'tls';
 
+        // Support implicit SSL by passing the URI scheme through to Net_Sieve -> Net_Socket -> stream_socket_client().
+        if ($scheme === 'ssl') {
+            $host = 'ssl://' . $host;
+        }
+
         if (empty($port)) {
             $port = getservbyname('sieve', 'tcp') ?: self::PORT;
         }