diff --git a/data/Dockerfiles/dovecot/imapsync_runner.pl b/data/Dockerfiles/dovecot/imapsync_runner.pl
index 9eaf5f4314..8bfc298b04 100644
--- a/data/Dockerfiles/dovecot/imapsync_runner.pl
+++ b/data/Dockerfiles/dovecot/imapsync_runner.pl
@@ -150,6 +150,7 @@ sub sig_handler {
   "--passfile1", $passfile1->filename,
   "--port1", $port1,
   "--host2", "localhost",
+  (!exists($ENV{IMAP_PORT})? () : ('--port2', $ENV{IMAP_PORT})),
   "--user2", $user2 . '*' . trim($master_user),
   "--passfile2", $passfile2->filename,
   ($dry eq "1" ? ('--dry') : ()),