From 36921dd29f3cd16ed726153b24ac939deef0bfd9 Mon Sep 17 00:00:00 2001 From: holger krekel Date: Tue, 12 May 2026 06:56:11 +0200 Subject: [PATCH] fix: advertise 8BITMIME to prevent conversion after DKIM signing (#149) for bounces postfix sets Content-Transfer-Encoding: 8bit which causes a quoted-printable conversion when filtermail SMTP does not offer 8BITMIME, which in turn breaks DKIM verification. --- filtermail/src/smtp_server.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/filtermail/src/smtp_server.rs b/filtermail/src/smtp_server.rs index 1a7f8178..62aef491 100644 --- a/filtermail/src/smtp_server.rs +++ b/filtermail/src/smtp_server.rs @@ -121,7 +121,7 @@ where || cmd.to_uppercase().starts_with("LHLO") { writer - .write_all(b"250-filtermail\r\n250-XFORWARD ADDR\r\n250 OK\r\n") + .write_all(b"250-filtermail\r\n250-XFORWARD ADDR\r\n250-8BITMIME\r\n250 OK\r\n") .await?; writer.flush().await?; } else if cmd.to_uppercase().starts_with("MAIL FROM:<>") {