removed unused etc files

postfix/Dockerfile

@@ -4,13 +4,13 @@ FROM ubuntu:20.04
 ENV TZ Europe/Berlin 
 RUN <<EOF
 apt-get update
-apt-get install -y postfix
+apt-get install -y postfix bind9-dnsutils
 # cleanup
 apt-get autoclean
 rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* ~/.cache ~/.npm
-echo zntrl.de >>/etc/mailname
 EOF
 COPY etc/postfix/ /etc/postfix/
+RUN cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf
 COPY --chmod=0775 entrypoint.sh /entrypoint.sh
 EXPOSE 25
 VOLUME /var/spool/postfix

postfix/entrypoint.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env sh
-# set -e
-cd /etc/postfix
-postmap virtual
-postmap vmailbox
+set -e
+# https://serverfault.com/questions/1003885/postfix-in-docker-host-or-domain-name-not-found-dns-and-docker
+cp /etc/resolv.conf /var/spool/postfix/etc/resolv.conf
+postmap /etc/postfix/virtual
+postmap /etc/postfix/vmailbox
 exec "$@"

postfix/etc/postfix/main.cf

@@ -10,17 +10,17 @@ append_dot_mydomain = no
 #delay_warning_time = 4h
 readme_directory = no
 
-# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
-# fresh installs.
+# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on fresh installs.
 compatibility_level = 2
 
 # local domains
-myhostname = nuc0.fritz.box
-mydestination = $myhostname, localhost.fritz.box, localhost
+myhostname = mta.zntrl.de
+mydestination = $mydomain, localhost.$mydomain, localhost
 alias_maps = hash:/etc/aliases
 alias_database = hash:/etc/aliases
-myorigin = /etc/mailname
-mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
+myorigin = zntrl.de
+# mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
+mynetworks_style = subnet
 
 # virtual domains
 virtual_mailbox_domains = zntrl.de 
@@ -32,7 +32,7 @@ virtual_transport = lmtp:dagent:2003
 # default domains
 default_transport = smtp:[relay.zntrl.de]:465
 
-# SMPTD (inbound) TLS parameters
+# SMTPD (inbound) TLS parameters
 smtpd_tls_CApath = /etc/ssl/certs
 smtpd_tls_CAfile = /etc/postfix/ssl/certs/balusign-signing-ca.pem
 smtpd_tls_cert_file = /etc/postfix/ssl/nuc0-full-chain.pem
@@ -56,4 +56,3 @@ message_size_limit = 50000000
 recipient_delimiter = +
 inet_interfaces = all
 inet_protocols = all
-

postfix/etc/postfix/virtual

@@ -1,3 +1,3 @@
 postmaster@zntrl.de postmaster
-abuse@zntrl.de  postmaster
+abuse@zntrl.de      postmaster