spam filter on iPhone Mail app?

What email are you using? Gmail, AOL, Yahoo all have their own spam filters and work fine for me on my iPhone.

The iphone does not have a spam filter in the mail app.

Depending on your e-mail provider, you can set up spam filters on the server.

I do have the spam folder when I log on to a computer. However, that folder does not transmit to the iPhone. Could someone tell me how to place it onto the iPhone? ATT Yahoo said it was an Iphone issue.

Not possible with a POP account.

With an IMAP account, all server stored mailboxes for the account are kept synchronized with the server automatically with each email client used to access the account.

I access a MobileMe account and a business POP account with my iPhone. I have selected to store the Junk mailbox for my MM account on the server with the Mail.app on my Mac and with the iPhone's mail client. I keep the Mail.app on my Mac launched and running which includes a spam filter - but I rarely receive spam with the account. If my MM account receives a junk message that is marked as junk with the spam filter with the Mail.app on my Mac, the message is moved to the account's Junk mailbox which is stored on the server. This is reflected automatically when checking the account with the iPhone's mail client, so in effect, I do have the junk mail filter included with the Mail.app on my Mac with the iPhone's mail client. The only difference being I can't mark a message as junk with the iPhone's mail client, but I can transfer a message received that is junk (that isn't marked as junk when received by the Mail.app on my Mac) to the account's junk mailbox which is stored on the server.

None of this is possible with a POP account.

Even if a junk mail filter was available with the iPhone's mail client, it wouldn't match the junk mail filter's learned settings with the email client used on your computer for accessing the account.

Just so I understand, if you have a MM account and under the account settings, you choose to store the junk mail on the server, the iPhone will honor the junk mail settings the same as the mail.app?

If you are accessing a MM account as an IMAP account with the Mail.app on your Mac and with the iPhone's mail client, and you have selected to store the account's Junk mailbox on the server with both email clients, all server stored mailboxes with an IMAP account are kept synchronized with the server automatically with each email client used to access the account.

Keep the Mail.app on your Mac launched and running automatically checking for new messages every 5 minutes, and any spam that is marked as junk with the Mail.app's junk mail filter, which will be moved to the account's junk mailbox stored on the server will be reflected automatically when checking the account with the iPhone's mail client.

The same applies to any IMAP account.