[Doc HM]

Phew, troublesome

Although mail.app has its shortcomings it generally pretty reliable, however having spent the afternoon battling against it for a client it seems it's hiding some nasty practises.

Anyway, clients mail worked fine on his iMac but if he opened up his MacBook, or attempted to check mail on his iPad or iPhone then all his devices would suddenly no longer connect to the mail server.

After plenty of digging it turns out that mail.app opens up multiple connections to a mail server, in this case enough that the server would refuse anymore connections. The only fix being to quit mail on one Mac and not check on iOS devices until the server had cleared it's connections.

Having not seen this issue before it seems like a combination of bad practice on mail.apps part combined with the iso limiting simultaneous connects to a number low enough to cause mail issues.

My client didn't want to change mail application or provider, luckily we could upgrade his account to a full exchange server which solved the issues.

Any comments on this from more mail knowledgable members?

[besson3c]

I like being paged, it makes me feel loved and needed!

This is definitely Mail.app's fault, Mail is horrible about opening more connections than the spec documents, and it may not just be Mail.app but the iOS mail app too (at least this used to be the case).

The only solutions that I can think of are a mail server config adjustment, or a client change.

Edit: you could also disable IMAP IDLE in Mail.app, that might help. Server admins can adjust timeout values too.

[besson3c]

Caveat: the IMAP IDLE setting will only be relevant if the server supports this in the first place. If it doesn't this setting will just be ignored - you won't get an error message or anything like that.

[Doc HM]

Disabling/enabling IDLE made no difference, which was as expected. The isp do support it.

tech support there identified mail as opening 5 simultaneous connections, closing 2, idling 2 and opening five more, all within a fraction of a second. Nonsense.

There was nothing they were prepared to alter at there end, they said it was Apples fault for building a rubbish mail client. While this issue has not effected any of my other clients (so it could also be said that the iso is too limiting on it's allowance for connections) going to exchange is the fix de jour.