1 files changed, 6 insertions, 2 deletions
diff --git a/lib/Net/IMAP/Sync.pm b/lib/Net/IMAP/Sync.pm
index 4a9d431..85ca487 100644
--- a/lib/Net/IMAP/Sync.pm
+++ b/lib/Net/IMAP/Sync.pm
@@ -347,9 +347,13 @@ sub new($%) {
         elsif ($mech eq 'PLAIN') {
             require 'MIME/Base64.pm';
             $self->fail("Missing option $_") foreach grep {!defined $self->{$_}} qw/username password/;
-            $command = "AUTHENTICATE $mech";
             my $credentials = MIME::Base64::encode_base64("\x00".$username."\x00".$password, '');
-            $callback = sub($) {return $credentials};
+            $command = "AUTHENTICATE $mech";
+            if ($self->_capable('SASL-IR')) { # RFC 4959 SASL-IR
+                $command .= " $credentials";
+            } else {
+                $callback = sub($) {return $credentials};
+            }
         }
         else {
             $self->fail("Unsupported authentication mechanism: $mech");