iOs 4 sometimes slows down Exchange and either does not sync or does it slowly

Apple published a bulletin with a very interesting description: Exchange ActiveSync Mail, Contacts, or Calendars do not synchronize or do it very slowly. At the same time, some Exchange administrators note the slow operation of the servers.
Apple recommends installing the update on all phones used by the company, if possible.

The treatment is simple: you need to start Safari and download the configuration profile. You must install it despite the warning about the lack of a digital signature.
After installation, profile can be found in Settings> General> Profile.
The essence of the profile is to change the wait timeout.

So think after that what you want.
I dare to assume that the phones pass authentication, and then, without waiting for a response, they send a new request. So it turns out DoS.