Adding Exchange ActiveSync configs to the Mozilla ISP DB?

Kent James kent at
Fri Nov 30 18:31:44 UTC 2012

On 11/30/2012 1:56 AM, Christian Rößner wrote:
> Hi,
> I am not sure, if I got the point of this topic and this is my first post here, so hopefully I can provide useful information.
I sort of introduced a digression (discussing details of how to do 
autodiscover) when the original topic was whether to add the 
autodiscover URL to the ispdb. But continuing with my digression ...

>>> Exchange does have the Autodiscovery service, which we already try in our code. The logic is as follows ...
>> You are leaving out 2 steps of Microsoft Autodiscover. Is that intentional?
>> ...
>> A second is to lookup a DNS SRV record to find the autodiscover domain. This of course is a long-standing missing feature of Mozilla core code, and requires a separate service to implement.
>> These are the methods that would typically be used by someone who has outsourced email to a server on a different domain.
> I have written the code of automx (, which "tries" to implement the autoconfig and the autodiscover protocols. I already have done full support for autoconfig. AutoDiscover makes problems with SRV records (at least with iOS devices). I never tried GET-redirect method. Even thunderbird does not support SRV, you can use redirect perfectly. So I see no missing feature here.

When trying to support auto configure, particularly for a minority email 
client like Thunderbird that may be used in an environment where the 
majority of users are on another client, then the issue is not what it 
is possible for the email admin to figure, but whether we support what 
they actually configured. I actually have some data on this. Taking a 
manual sample of recent requests for autodiscover to my ExQuilla 
extension, 18 of 130 unique domains had SRV records configured for 
autodiscover. I suspect that a fairly sizable fraction of the (130 -18) 
that did not have SRV records had no autodiscover configured at all, so 
a fairly sizeable fraction of autodiscover sites use a SRV record. 
Ignoring that will cause autodiscover to fail much more than it should.

A SRV record has a big advantage over other methods (it does not require 
that a webserver exist at the domain name, or if it does exist it does 
not require the email admin group to administer either a subdomain or 
redirect at that site), so I would say that the SRV record is actually 
the preferred way to deliver an autodiscover URL.


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