Push Email on Wifi Not Working

I have been keeping my wifi on at work during the day and have noticed that I don't seem to be getting push email from exchange when the wifi is on. If I turn the wifi off, suddenly all of my emails come in. I am trying to use the stock email app, which I love, but this is a serious failure for me. Anyone have any ideas of what might be going on, or is anyone else experiencing the same issue? Gmail and all other push services seem to work fine, only the mail app seems to have this issue. I've searched Google high and low and haven't been able to find any other posts for a similar issue, so I'm starting to wonder if it is just me. Thanks.