mod_sasl2: Pull user-agent info into sasl_handler for later reference It may be of interest to post-auth things. Putting it on the session was another option considered, but that seemed unnecessary overhead for something that might be rarely used. sasl_handler is cleared after successful authentication.

This module lets you block connections to remote servers at the s2s
level.

``` {.lua}
modules_enabled = {
    -- other modules --
    "s2s_blacklist",

}
s2s_blacklist = {
    "proxy.eu.jabber.org",
}
```