iChat: Cannot Send or Receive a File When Firewall Is Active

Symptom

iChat cannot send or receive a file when the Mac OS X firewall is active in its default state. If you have opened the AIM port, you may be able to receive a file but not send them.


Solution

In its default state, the Mac OS X firewall blocks file transfers using iChat or America Online AIM software. If either the sender or receiver has turned on the Mac OS X firewall, the transfer may be blocked.

The simplest workaround is to temporarily turn off the firewall in the Sharing preference pane on both computers. This is required for the sender. However, the receiver may keep the firewall on if the AIM port is open. To open the AIM port:

1. Choose Apple menu > System Preferences.
2. Choose View > Sharing.
3. Click the Firewall tab.
4. Click New.
5. Choose AOL IM from the Port Name pop-up menu. The number 5190 should already be filled in for you.
6. Click OK.

If you do not want to turn off firewall at the sending computer, a different file sharing service may be used instead of iChat. The types of file sharing available in Mac OS X are outlined in technical document 106461, "Mac OS X: File Sharing".

Note: If you use a file sharing service when the firewall is turned on, be sure to click the Firewall tab and select the service you have chosen in the "Allow" list. If you do not do this, the firewall will also block the file sharing service.

This document will be updated as more information becomes available.