mod_s2s_keepalive: Ignore errors from the local server If a stanza can't be delivered and instead an bounce is generated, the origin of the error, when different from the stanza 'from' should be indicated in the 'by' attribute of the <error>, which we look for here so this doesn't count as a successful ping. An error that does come from the remote means we have connectivity, but probably no XEP-0199 handling. This is fine. We care about connectivity, not protocol.

Introduction
============

This module attempts to sanitize XHTML-IM messages.

It does **not** attempt to sanitize any CSS embedded in `style`
attributes, these are instead stripped by default.

Configuration
=============

  Option                   Type      Default
  ------------------------ --------- ---------
  `strip_xhtml_style`      boolean   `true`
  `bounce_invalid_xhtml`   boolean   `false`