If an organization is using Microsoft SBS 2011, can they configure it to support Variable Envelope Return Path (VERP) for the required CiviMail mailbox(es)? What implications will this have on bounce handling if not?

2 Answers 2


No version of Exchange supports subaddressing.

  • You could have a workaround by using a catchall. but honestly at that point, is this really a battle worth fighting?
    – Xavier
    May 8, 2015 at 7:20
  • No, it's not worth the effort IMO ... We have a dedicated domain that we use for clients who lack decent mail support, and we could MX crm.example.org there, so yeah we'll probably sidestep the issue rather than engaging it directly. May 9, 2015 at 7:30

It shouldn't be too complicated to modify civicrm to be able to process bounces without VERP:

We've added the same information that the VERP contains (basically who was the intended recipient) into the header of the message.

Most (but not all mail servers return these into the bounce notification message).

So if:

  • you add a config "no VERP"
  • you modify the smtp code to not add the VERP (so instead of [email protected], just [email protected])
  • you modify the parsing code for bounce messages to read the blablabla both from the mail address or from the header

It should work for most recipients mail servers, from the (dis)comfort of your exchange server.

PR welcome and all that

  • This would be a useful feature to get into core?
    – Graham
    May 8, 2015 at 10:02
  • Personally, compatibility with exchange isn't high on my list, but I see the benefit (that's why I added the "verp header" in the core already). The risk is that folks will use that inferior option even if they have a mail server that can actually handle VERP.
    – Xavier
    May 8, 2015 at 10:13
  • @Graham perhaps, but that means some org or devs putting further effort into implementing an (inferior, since reduced functionality) no-VERP approach, in a world where VERP-capable mailboxes are plentiful and cheap/free. Time better spent elsewhere IMO. May 9, 2015 at 7:27
  • Whilst I understand, and in many ways agree with Xavier and @Chris-burgess in that we do live in a world where VERP-capable mail systems are plentiful, we also live in a world where many potential users of CiviCRM already rely on Exchange. As a consequence of not supporting Exchange don't we make it harder for those orgs to successfully implement CiviCRM?
    – Graham
    May 18, 2015 at 12:18
  • CiviCRM supports using Exchange (civicrm.stackexchange.com/q/2322/149), but Exchange doesn't support VERP. CiviCRM can have even better Exchange support if/when someone contributes energy towards it. "Unless someone like you cares a whole awful lot, nothing is going to get better. It's not." :) Scratch your own itches; if that seems like a good place for your org to contribute, go for it! May 18, 2015 at 19:35

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