diff --git a/pkgs/servers/mail/postfix/default.nix b/pkgs/servers/mail/postfix/default.nix
index 019cc1b1948c..a418e2af4685 100644
--- a/pkgs/servers/mail/postfix/default.nix
+++ b/pkgs/servers/mail/postfix/default.nix
@@ -79,6 +79,8 @@ in stdenv.mkDerivation rec {
     make makefiles CCARGS='${ccargs}' AUXLIBS='${auxlibs}'
   '';
 
+  NIX_LDFLAGS = lib.optional withLDAP "-llber";
+
   installTargets = [ "non-interactive-package" ];
 
   installFlags = [ "install_root=installdir" ];