IPhone supports IMAP. The IMAP protocol allows you to receive your emails without downloading them from the server. IMAP also supports folders. Follow these steps to create an IMAP connection for your iPhone or iPhone 3G with Firmware 2.0.x:
1.On iPhone, select Settings.
2.Then Mail, Contacts, Calendars.
3.Select Add Account.
5.Click Add Mail Account.
6.Fill in the Name, Address (full email) and Password fields.
7.Click on Next.
8.Confirm that IMAP is selected.
9.Enter the incoming mail server data: < > Hostname is mail.yourdomain.comUsername is your full email addressPassword is the same you use to access via webmail / POP3 / IMAP / SMTP
10.Enter your outgoing mail server data: < > Hostname is mail.fullscreen.comUsername is your full email addressPassword is the same you use to access via webmail / POP3 / IMAP / SMTP
12.IPhone will try to establish an SSL connection to IMAP and SMTP servers. If it fails you will see the "Do you want to try setting up the account without SSL?" Dialog box <> Select No. Click Save. When asked "This account may not be able to send or receive emails. Are you sure you want to save? " Choose Save.
13.Click the account you just added (identified by your email address)
14.Swipe down and select the SMTP button.
15.Select the server you just added, identified by Host Name in step 9.
16.Select OFF to Use SSL.
17.Select Password for Authentication
18Select 587 for Server Port.
19.Click the SMTP button to go back.
20.Click on your email address to go back.
21.Click on Advanced.
22.Swipe down to Input Settings.
23.Select OFF to Use SSL.
24.Select Password for Authentication.
25.Select 143 for Server Port.
26.Click on your email address to go back.
27.Click Mail to go back.
28.Click on the Home button.
29.Click Mail App to verify your setting.