1 files changed, 3 insertions, 1 deletions

diff --git a/conf.d/040_transports.conf b/conf.d/040_transports.conf
index 5a829fb..543671f 100644
--- a/conf.d/040_transports.conf
+++ b/conf.d/040_transports.conf
@@ -33,12 +33,14 @@ DKIM_SIGN_HEADERS = _DKIM_SIGN_HEADERS
 DKIM_SIGN_HEADERS = In-Reply-To:Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID:Subject:To:From:Date:Sender:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive
 .endif
 
+DKIM_PRIVATE_KEY_FILE = DKIMDIR/$dkim_selector._domainkey.$dkim_domain.pem
+
 signed_smtp:
   driver             = smtp
   message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
   dkim_domain        = ${if def:authenticated_id {$sender_address_domain}}
   dkim_selector      = $primary_hostname
-  dkim_private_key   = DKIMDIR/$dkim_selector._domainkey.$dkim_domain.pem
+  dkim_private_key   = ${if exists{DKIM_PRIVATE_KEY_FILE}{DKIM_PRIVATE_KEY_FILE}{0}}
   dkim_canon         = relaxed
   dkim_strict        = yes
   dkim_sign_headers  = ${filter{DKIM_SIGN_HEADERS}{!eq{$item}{Sender}}}