diff --git a/ansible/roles/common_deb/defaults/main.yml b/ansible/roles/common_deb/defaults/main.yml
index 6581957d7cc4b3daee1363e2496a1480dd97d0be..446c4d0ef3a07ad780a85dff261323b34243e974 100644
--- a/ansible/roles/common_deb/defaults/main.yml
+++ b/ansible/roles/common_deb/defaults/main.yml
@@ -1,6 +1,6 @@
 tz: Europe/Prague
 mail_relay: relay.fi.muni.cz
-postfix: false
+postfix: true
 pam_use_kerberos: True
 backports_git: False
 backports: False
diff --git a/ansible/roles/common_deb/tasks/main.yml b/ansible/roles/common_deb/tasks/main.yml
index 1e44ab9cd09ad3ed74d5d993c8a5bfc308892ae9..0499aa46ecfc56c86ef680f20e815806fa7f76ce 100644
--- a/ansible/roles/common_deb/tasks/main.yml
+++ b/ansible/roles/common_deb/tasks/main.yml
@@ -118,6 +118,7 @@
   template:
     src: nftables.conf.j2
     dest: /etc/nftables.conf
+    validate: nft --check -f %s
   notify:
     - restart nftables
   when: nftables_default_config
@@ -259,6 +260,7 @@
       - moreutils
       - bat
       - iotop
+      - socat
 
 - name: monitoring
   apt: