diff --git a/group_vars/all/main.yml b/group_vars/all/main.yml
index 0d0e9fc..604f594 100644
--- a/group_vars/all/main.yml
+++ b/group_vars/all/main.yml
@@ -77,7 +77,7 @@ sshd_allowed_users: {}
 
 apt_manage_sources_list: true
 
-apt_src_enable: true
+apt_src_enable: false
 apt_backports_enable: true
 
 apt_debian_mirror: http://ftp.de.debian.org/debian/
diff --git a/roles/common/tasks/nis-install-client.yml b/roles/common/tasks/nis-install-client.yml
index 9bb7f7f..665b378 100644
--- a/roles/common/tasks/nis-install-client.yml
+++ b/roles/common/tasks/nis-install-client.yml
@@ -179,7 +179,7 @@
 - name: (nis-install-client.yml) Adjust file /etc/nsswitch.conf (set hosts)
   replace:
     path: /etc/nsswitch.conf
-    regexp: '(hosts:\s+files)\s+([^nis].*)'
+    regexp: '(hosts:\s+files)\s+((?!nis).*)$'
     replace: '\1 nis \2'
   tags:
     - nis-install
@@ -188,7 +188,7 @@
 - name: (nis-install-client.yml) Adjust file /etc/nsswitch.conf (set passwd/group/shadow)
   replace:
     path: /etc/nsswitch.conf
-    regexp: '^({{ item }}:\s+.*)'
+    regexp: '^({{ item }}:\s+((?!nis).)*)$'
     replace: '\1 nis'
   with_items:
      - passwd