Make sure 'localhost6' is in /etc/hosts
Add referer filtering in nginx server configs

As an option, in nginx server configuration definition you can define
list of domain names that are accepted as page referers. If a webpage is
linked from a different domain name than the accepted ones, it will be
blocked with error 403.
Add Mailman support in Postfix role

- when 'mailman' capability is enabled in 'postfix' role, Postfix will
  be configured to support Mailman aliases and/or transport;

- different configuration options will be enabled depending on wether
  you have 'local' capability enabled or disabled;

- with 'local' capability enabled, Postfix will use local aliases and
  virtual aliases/domains to pass mail messages to Mailman. Without
  'local' capability, Postfix will use relay transport and
  "postfix-to-mailman.py" Python script instead;
Add 'listmaster' default alias in Postfix role
Add 'mailman' role - Mailman mailing list manager

- Mailman role requires 'mailman' capability in Postfix. Should work
  with or without local delivery;

- by default, Mailman is configured with UTF-8 support. Some language
  packs provided in Mailman Wheezy packages are not currently converted to
  UTF-8. Mailman role provides support for Polish language conversion,
  with other languages as needed (pull requests welcome);

- Mailman installation will be patched and configured to provide strong
  anti-spam and anti-backscatter protection. By default, Mailman will
  discard e-mail messages from addresses not subscribed to a mailing
  list - as a tradeoff, users cannot subscribe via mail - subscription
  via web interface is mandatory. After subscription, mail commands will
  work as normal. Access to Mailman web interface is limited to
  a configurable set of domain referers, other domains will be blocked;

- default list of mailing list aliases (-request, -owner, etc.) is
  reduced to mitigate spamming and backscatter;

- Mailman role has support for multiple virtual domains. By default,
  mailing lists will be configured on 'lists.{{ ansible_domain }}' domain;
Specific configuration for Mailman in Travis CI
Merge pull request #46 from drybjed/role/mailman

Mailman mailing list manager support