Which mailserver status messages do you classify as "bounced"?

[Marcus]

I change user accounts to "bounced" when Í get a status=bounced from my mailserver.

But there are other status messages where the user account has to be updated. For example, when the mail can not be delivered because the mailserver can not be reached at all. There are other messages like "connection refused".

I found some error messages explained here: http://www.penpublishing.com/Support/EmailErrors/UnderstandingEmailErrors/

Then some users mailboxes are always full so the mail is not delivered. Some mailboxes are full and will never be empty. Do you filter out these messages, too? It is quite more difficult to check against whether the mailbox is full for a specific period. Or do you classify a mail as bounced the first time the mailbox is full? It is more uncommon this time to get this error. So these abandoned mailboxes might be from a different (internet) decade.

Which mailserver status messages do you classify as "bounced" in the way that you update your user accounts to "email bounced"?

 

[Alpha1]

Mail servers keep changing their status messages over the years and new mail servers become popular. We can't simply ignore mail servers that do not comply to standards, because by far most do not.

We define bounce rules first:

$GLOBALS['BOUNCE_RULES'] = array(
    'soft' => array(
        'inactive' => array(),
        'overquota' => array(),
        'blockedcontent' => array()
    ),
    'hard' => array(
        // we distinguish between the types so we can see the differences in the statistics area.
        'emaildoesntexist' => array(),
        'domaindoesntexist' => array(),
        'relayerror' => array(),
        'invalidemail' => array(),
        'inactive' => array(),
    ),
    'delete' => array(
        'delete' => array(),
    ),
);

Then we defined parts of text for each mail server and the bounce rule to which the text should be tied to. If that is recognized as a bounce rule, then it will be handled according to the settings in vbulletin acp. ACP has settings for each bounce rule, so the admin can fine tune. AFAIK there is no complete list of phrases. My list of 700 phrases was defined by going through tens of thousands of bounce messages manually for 5 months until all was covered at the time. This was 3 years ago. and an update is needed.