From cb62c69b43c4f1feae044d997f4ce398ffe586d0 Mon Sep 17 00:00:00 2001
From: AndrewPaglusch <AndrewPaglusch@users.noreply.github.com>
Date: Fri, 22 Aug 2025 00:40:21 -0500
Subject: [PATCH 1/2] add POSTFIX_STRIP_SENDER_HEADER var

---
 README.md                                   |  1 +
 rootfs/etc/cont-init.d/15-config-postfix.sh | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/README.md b/README.md
index d9f6166..ee8e1b2 100644
--- a/README.md
+++ b/README.md
@@ -158,6 +158,7 @@ linux/arm64
 
 * `POSTFIX_DEBUG`: Enable debug (default `false`)
 * `POSTFIX_MESSAGE_SIZE_LIMIT`: The maximal size in bytes of a message, including envelope information (default `26214400`)
+* `POSTFIX_STRIP_SENDER_HEADER`: Strip the Sender header from incoming emails to prevent SES rejection issues (default `false`)
 * `POSTFIX_SMTPD_TLS`: Enabling TLS in the Postfix SMTP server (default `false`, possible values: `true`|`may`|`encrypt`|`ask`|`require`, see [Postfix TLS README](https://www.postfix.org/TLS_README.html#client_tls_levels))
 * `POSTFIX_SMTPD_TLS_CERT_FILE`: File with the Postfix SMTP server RSA certificate in PEM format
 * `POSTFIX_SMTPD_TLS_ECCERT_FILE`: File with the Postfix SMTP server RSA private key in PEM format
diff --git a/rootfs/etc/cont-init.d/15-config-postfix.sh b/rootfs/etc/cont-init.d/15-config-postfix.sh
index ec96473..1be47ff 100755
--- a/rootfs/etc/cont-init.d/15-config-postfix.sh
+++ b/rootfs/etc/cont-init.d/15-config-postfix.sh
@@ -257,6 +257,20 @@ EOL
 chmod o= /etc/postfix/mysql-virtual-alias-domains-and-subdomains.cf
 chgrp postfix /etc/postfix/mysql-virtual-alias-domains-and-subdomains.cf
 
+if [ "$POSTFIX_STRIP_SENDER_HEADER" = "true" ]; then
+  echo "Setting Postfix header_checks to strip Sender header"
+  cat >/etc/postfix/header_checks <<EOL
+/^Sender:/      IGNORE
+EOL
+  cat >>/etc/postfix/main.cf <<EOL
+
+# Header checks configuration
+mime_header_checks = regexp:/etc/postfix/header_checks
+header_checks = regexp:/etc/postfix/header_checks
+EOL
+  postmap /etc/postfix/header_checks
+fi
+
 if [ -f "/data/postfix-main.alt.cf" ]; then
   cat "/data/postfix-main.alt.cf" > /etc/postfix/main.cf
 fi

From cbe414de3c48effecab1cc2560ae8a51e8cf6176 Mon Sep 17 00:00:00 2001
From: CrazyMax <1951866+crazy-max@users.noreply.github.com>
Date: Sun, 19 Oct 2025 21:24:03 +0200
Subject: [PATCH 2/2] set default value for POSTFIX_STRIP_SENDER_HEADER env

---
 rootfs/etc/cont-init.d/00-env | 1 +
 1 file changed, 1 insertion(+)

diff --git a/rootfs/etc/cont-init.d/00-env b/rootfs/etc/cont-init.d/00-env
index ff9fa45..a5baed1 100755
--- a/rootfs/etc/cont-init.d/00-env
+++ b/rootfs/etc/cont-init.d/00-env
@@ -83,6 +83,7 @@ MAIL_ENCRYPTION=${MAIL_ENCRYPTION:-null}
 
 POSTFIX_DEBUG=${POSTFIX_DEBUG:-false}
 POSTFIX_MESSAGE_SIZE_LIMIT=${POSTFIX_MESSAGE_SIZE_LIMIT:-26214400}
+POSTFIX_STRIP_SENDER_HEADER=${POSTFIX_STRIP_SENDER_HEADER:-false}
 POSTFIX_SMTPD_TLS=${POSTFIX_SMTPD_TLS:-false}
 POSTFIX_SMTP_TLS=${POSTFIX_SMTP_TLS:-false}
 POSTFIX_RELAYHOST_AUTH_ENABLE=${POSTFIX_RELAYHOST_AUTH_ENABLE:-false}