IChat video & screen share failure

Question

using iChat 5.0.3 on a new iMac. I can initiate a request to share screen or video chat but fails to start. I am on 10.6.4. Under connection doctor, Router type light is YELLOW and states it is Symmetric and that the network's setup includes one or more devices that are not fully compatible with audio and video chatting.
What gives? It used to work fine on a previous iMac here. Sounds like a network issue but don't know where to start.

Answer 1

Hi,
This is a link to a Site Called Port Forwarding and the info for TX 170 (they did not list the TZ 100)
Do this pages look similar to yours ?
The third Sonicwall pic shows the Firewall > Services page open (where Port Forwarding is done.)
We are not looking at this stage to Do Port Forwarding.
In Firewall > Advanced does it have UPnP ?
Are there any Port Forwarding settings made ?
Are they for iChat ?
On your TZ 100 pages does it list an IP the ports are pointing to ? (Port Forwarding in many devices lists an IP (Computer) that has access to those ports - excluding others - possibly you new computer if it has s different IP)
I see here that it has Stateful Packet Inspection (SPI) which can be a feature that gets in the way of iChat.
I cannot read anything there that says it does UPnP.
You may also need to look and what it is doing for VoIP.
VoIP is Voice over Internet (IP Phones and devices) It uses the SIP (Session Intiation Protocol) to connect either a device (phone or adapter) or in some cases software that acts like a phone over the internet.
However iChat also uses SIP to connect.
VoIP used to be pushed over port 5060-5063 and some devices still make sure all SIP data uses one of these ports (5060 is the most common).
iChat does not use port 5060 for SIP since iChat 4 came out and any redirection by the TZ 100 maybe the issue.
If you cannot find UPnP on any page on the device you will have to set Port Forwarding.
You will need these ports
||iChat Ports||TCP||UDP||
|AIM|5190|5190|
|A/V|none|5678, 16393-16402|
|Bonjour|5298|5297, 5298, 5353|
|Jabber|5220,5222, 5223|none|
Note this is the iChat 4 and 5 Range
Add port 5060 UDP for iChat 2 and 3 and extend the group of 10 to 16384-16403 (20 ports)
iChat 4 and 5 also uses an undeclared Random port to do the Screen Sharing part and works if you can and do use UPnP (Or Port Mapping Protocol) to open ports in your routing device.
As you cannot set the random port you will not be able to Screen Share.
10:18 PM Thursday; September 16, 2010
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