diff --git a/krebs/3modules/exim-retiolum.nix b/krebs/3modules/exim-retiolum.nix
index 6e6928f89..696c48baf 100644
--- a/krebs/3modules/exim-retiolum.nix
+++ b/krebs/3modules/exim-retiolum.nix
@@ -39,6 +39,8 @@ let
         # TODO modular configuration
         assert config.krebs.retiolum.enable;
         ''
+          keep_environment =
+
           primary_hostname = ${cfg.primary_hostname}
           domainlist local_domains = ${concatStringsSep ":" cfg.local_domains}
           domainlist relay_to_domains = ${concatStringsSep ":" cfg.relay_to_domains}
diff --git a/krebs/3modules/exim-smarthost.nix b/krebs/3modules/exim-smarthost.nix
index c976e89de..93e4deace 100644
--- a/krebs/3modules/exim-smarthost.nix
+++ b/krebs/3modules/exim-smarthost.nix
@@ -75,6 +75,8 @@ let
     services.exim = {
       enable = true;
       config = ''
+        keep_environment =
+
         primary_hostname = ${cfg.primary_hostname}
 
         # HOST_REDIR contains the real destinations for "local_domains".