We have an Exchange 2003 SP2 front end and Exchange 2003 SP2 back end server in our organization. We have activesync configured and users have iphones. We can successfully create Exchange profile on iphones and vaildate with the user credentials. The iphones are configured for PUSH so that emails are instantly delivered to the iphones. However, its taking about 15- 20 minutes for the emails to get to iphones. We have ensured that idle timeouts on firewall are set to 60 minutes and added registry settings on Front End Exchange for min and max heartbeat interval. We see pings in IIS logs. However , it takes 15 - 20 minutes for the emails to be pushed to iphones.If the mail app is opened on iphone,new emails appear instantly.Can somebody please suggest some troubleshooting steps?
Software/Hardware used: Exchange 2003 SP2 Front End and Back End