diff --git a/install_postfix_advanced.sh b/install_postfix_advanced.sh
index 9dc03cf..ef3ca0b 100755
--- a/install_postfix_advanced.sh
+++ b/install_postfix_advanced.sh
@@ -1747,15 +1747,68 @@ cat <<EOF >> /etc/postfix/main.cf
 
 # ============ TLS parameters ============
 
-## - supports DNSSEC
-## -
-## - !! Notice !!
-## - In order to support DNSSEC and DANE your resolver MUST support
-## - DNSSEC too.
-## -
-## - If your resolver does not support DNSSEC, install "unbound".
-## -
+
+# What mechanisms the Postfix SMTP client uses to look up a host's IP address.
+# This parameter is ignored when DNS lookups are disabled (see: disable_dns_lookups
+# and smtp_dns_support_level). The "dns" mechanism is always tried before "native"
+# if both are listed.
+#
+# Specify one of the following:
+#
+#  dns
+#     Hosts can be found in the DNS (preferred).
+#
+#  native
+#     Use the native naming service only (nsswitch.conf, or equivalent mechanism).
+#
+#  dns, native
+#     Use the native service for hosts not found in the DNS.
+#
 smtp_host_lookup = dns
+
+# Level of DNS support in the Postfix SMTP client. With "smtp_dns_support_level"
+# left at its empty default value, the legacy "disable_dns_lookups" parameter c
+# ontrols whether DNS is enabled in the Postfix SMTP client, otherwise the l
+# egacy parameter is ignored.
+#
+#  Specify one of the following:
+#
+#  disabled
+#     Disable DNS lookups. No MX lookups are performed and hostname to address lookups
+#     are unconditionally "native". This setting is not appropriate for hosts that
+#     deliver mail to the public Internet. Some obsolete how-to documents recommend
+#     disabling DNS lookups in some configurations with content_filters. This is no
+#     longer required and strongly discouraged.
+#
+#  enabled
+#     Enable DNS lookups. Nexthop destination domains not enclosed in "[]" will be
+#     subject to MX lookups. If "dns" and "native" are included in the "smtp_host_lookup"
+#     parameter value, DNS will be queried first to resolve MX-host A records, followed by
+#     "native" lookups if no answer is found in DNS.
+#
+#  dnssec
+#     Enable DNSSEC lookups. The "dnssec" setting differs from the "enabled" setting above
+#     in the following ways:
+#
+#        - Any MX lookups will set RES_USE_DNSSEC and RES_USE_EDNS0 to request DNSSEC-validated
+#          responses. If the MX response is DNSSEC-validated the corresponding hostnames are
+#          considered validated.
+#
+#        - The address lookups of validated hostnames are also validated, (provided of course
+#          "smtp_host_lookup" includes "dns", see below).
+#
+#        - Temporary failures in DNSSEC-enabled hostname-to-address resolution block any
+#          "native" lookups. Additional "native" lookups only happen when DNSSEC lookups
+#          hard-fail (NODATA or NXDOMAIN).
+#
+# default: empty
+#
+# !! Notice !!
+# In order to support DNSSEC and DANE your resolver MUST support
+# DNSSEC too.
+#
+# If your resolver does not support DNSSEC, install "unbound".
+#
 smtp_dns_support_level = dnssec
 
 ## - Aktiviert TLS für den Mailempfang