iChat 3 Problems

Hi All,

"Not enough Bandwidth" error messages.

Steps to possible solution (this will not work for everyone).
Previous Panther users are the most likely effected by the solutions here.

Delete the iCAR add-on as it is not compatible with iChat 3
Delete the Panther version of Virex if you downloaded it from Apple as part of a @mac.com account. This is not compatible with Tiger.

Both the above will also produce the 1fps problem as well.

Check the System Preference Settings for all the following:
Quicktime Streaming speed - set greater or at least equal to your Uplink speed.
Network - Add DNS servers.
Date & Time - sync with Network server and Time Zone.
Sharing > Firewall - Check the Advanced button and make sure UDP ports are NOT Blocked
Sharing > Firewall - If on check the ports are open to UDP as well as the Panther TCP settings. (Old Panther settings will be there but will effectively block UDP ports if not changed).

Next check with a known good iChat account - either those from the FAQ list or the AIM account names tryichatav, appleu3test02 or appleu3test03. These last three accounts provide an Auto reponse for testing.

AT this point some of you will still have problems.
You need to talk to your ISPs and have them check the connection you have. In particular you may need to hint at checking Packet Header loss

If you have no luck then post in the Apple iChat 3 Discussion Area with details of the steps taken, the ISP and your Geographical location. Join other threads to keep the info in one place.

Ralph

iChat AV 3

Hi,

Well I have at last updated to Tiger.

iChat 3 is out and running.

Things that are obvious.

Buddy list is now tabbed for the groups that you have if Show Groups is selelcted in the View menu

The Preferences has a better to understand interface.

Not only does your Mac have to be fast enough to host the controller of multiple person Video chats but your Uplink speed has to be sufficient as well

Page is for iChat 3 to follow.

Should include some pictures.

Ralph

New email link

Hi,

I plan to add and Email link butin the mean time.

Use this ralphjohns@lineone.net


Ralph

Interesting email

Hi All,

I have received this email which points out the differences between Port Forwarding and NAT

Hello Ralph

You have kindly responded to my post about lack of repeatability when using iChatAV for video chat through NAT. Indeed I see that you are very responsive to many queries and others often refer to your helpful Web site.

Offline, I have a comment on the reference you have in your pages to NAT and port forwarding - saying that effectively they are the same thing. I think that it may not help some people to see it this way.

For most situations when connecting from a private network to the Internet via a NAT device the concern is for outgoing or dynamic NAT. Traffic initiated from the inside (private) network has the source address translated to (usually) the public address of the outside interface of the NAT device. In many cases, the source port is translated as well. This is so that reply traffic carries enough information to allow the destination address to be translated to the correct inside address (and port). Replies will come back to the new port which the NAT device uses to look up from its dynamic tables where it should send the reply packets back to.

So reply traffic is allowed in automatically - provided the dynamic NAT tables have not timed out.

What Apple are trying to do is to have one end originate traffic from their iChat AV so that the other end sees it as reply traffic to its own outgoing packets. It is a trick that depends on the NAT device making certain "consistent" choices in how to do the port mapping. This presumably is what routers compatible with iChatAV do - including the Airport Extreme. The trick depends on their being a third-party mediator site and is similar to STUN - Apple say they would have used STUN if they had known about it at the time.
See for example http://www.voip-info.org/wiki-STUN and http://www.newport-networks.com/whitepapers/fwnatwpes3.html

See http://midcom-p2p.sourceforge.net/ for a related test tool. This is not perfect for iChatAV troubleshooting as it reports "consistent" for my Cisco router and for my son's Vigor router (once he had upgraded the firmware) but we could still not establish a video chat.

Port forwarding, on the other hand, sets up a static mapping for traffic originating from the outside to a particular inside address (and possibly port). It is provided for cases where there is a server such as a Web server on the private network. Its use is suggested by Apple for NAT devices that do not do outgoing (dynamic) NAT in the way needed for its trick to work. It is not the best choice to make from the security point of view because of the fact that it is a static (fixed, permanent) mapping allowing outside traffic to reach the inside irrespective of outgoing traffic.

Our problem comes of course because NAT (static and dynamic) was designed for client-server applications and not peer-to-peer applications such as direct video chat.

Just to clarify again the reason for my post, having obtained an Airport Extreme because it is a device on the list of NAT devices that work (ie do NAT in the way Apple needs) I was able to establish a video chat once but not a second time. I have not yet been able to try again after a long delay (to allow any NAT timers to time out) in case that was causing the problem.

Many regards

I wonder if any would find these distinctions helpful.

Comments welcome.

Ralph

Iteresting email

HI All,

I received this email which questions the info on this site regarding the differences between NAT and Port Forwarding.

Hello Ralph

You have kindly responded to my post about lack of repeatability when using iChatAV for video chat through NAT. Indeed I see that you are very responsive to many queries and others often refer to your helpful Web site.

Offline, I have a comment on the reference you have in your pages to NAT and port forwarding - saying that effectively they are the same thing. I think that it may not help some people to see it this way.

For most situations when connecting from a private network to the Internet via a NAT device the concern is for outgoing or dynamic NAT. Traffic initiated from the inside (private) network has the source address translated to (usually) the public address of the outside interface of the NAT device. In many cases, the source port is translated as well. This is so that reply traffic carries enough information to allow the destination address to be translated to the correct inside address (and port). Replies will come back to the new port which the NAT device uses to look up from its dynamic tables where it should send the reply packets back to.

So reply traffic is allowed in automatically - provided the dynamic NAT tables have not timed out.

What Apple are trying to do is to have one end originate traffic from their iChat AV so that the other end sees it as reply traffic to its own outgoing packets. It is a trick that depends on the NAT device making certain "consistent" choices in how to do the port mapping. This presumably is what routers compatible with iChatAV do - including the Airport Extreme. The trick depends on their being a third-party mediator site and is similar to STUN - Apple say they would have used STUN if they had known about it at the time.
See for example http://www.voip-info.org/wiki-STUN and http://www.newport-networks.com/whitepapers/fwnatwpes3.html

See http://midcom-p2p.sourceforge.net/ for a related test tool. This is not perfect for iChatAV troubleshooting as it reports "consistent" for my Cisco router and for my son's Vigor router (once he had upgraded the firmware) but we could still not establish a video chat.

Port forwarding, on the other hand, sets up a static mapping for traffic originating from the outside to a particular inside address (and possibly port). It is provided for cases where there is a server such as a Web server on the private network. Its use is suggested by Apple for NAT devices that do not do outgoing (dynamic) NAT in the way needed for its trick to work. It is not the best choice to make from the security point of view because of the fact that it is a static (fixed, permanent) mapping allowing outside traffic to reach the inside irrespective of outgoing traffic.

Our problem comes of course because NAT (static and dynamic) was designed for client-server applications and not peer-to-peer applications such as direct video chat.

Just to clarify again the reason for my post, having obtained an Airport Extreme because it is a device on the list of NAT devices that work (ie do NAT in the way Apple needs) I was able to establish a video chat once but not a second time. I have not yet been able to try again after a long delay (to allow any NAT timers to time out) in case that was causing the problem.

Many regards

I am not sure that this would be helpful to many of the people visiting this site.

Comments welcome

Ralph

Checking the AIM Server is online

Hi All

As you know you can access the Server Options Button in Accounts section of the iChat Preferences when you are not logged into AIM

The default server is called login.oscar.aol.com and the port is 5190.

Some people have found success with port 443

There is another server you can use:
login.glogin.messaging.aol.com
This would be worth trying.

If you still can not log on it will be worth checking with the Network Utility (Applications/Utilities) whether you can see the server.

Open Network Utility
Use the Ping tab
Enter either of the server names
Set the number of pings to 10.
Click the Ping button on the right.

This should confirm that the Server is answering. (or Not)

Also use the Port Scan tab
Enter either of the server Names
Limit the scan to start port 5190 and end port 5190

This should indicate if the port can be seen by you and is available. (or not)

You can take it the server is offline if you do not get a respose with these tests.

Ralph

New Blog Page Set up.

Hi All,

As you may have noticed this page now matches my other pages more closely.

Ralph

New Error message

Hi All,

Cooky94 on the Apple IChat Discussions had this error message

"NSImageCasheExcetion Cannot Cashe Image"

It is solved by checking for corrupted Buddy icons in com.apple.ichat.pictures which is in
Users/(your Account/Library/Caches.

Ralph

Port numbers for Triggering and Forwarding

Hi All,

Check this page for links to the router/modem you have:
http://www.portforward.com/routers.htm
Click on the name of the device and then the method of opening ports on the next page.

Use Port Triggering if you have several computers.
Use either if you have only one.

For Triggering you need to set up this table.
Trigger port 5678 to trigger ports 5678, 5060, 16384-16403
Trigger port 5190 to trigger port 5190

IF you have other Macs add these three entries.
Trigger port 5297 to trigger port 5297
Trigger Port 5298 to trigger port 5298
Trigger port 5353 to trigger port 5353

If this device needs to set protocols in the set up table all need UDP.

Ports 5190 and 5298 need TCP as well (might be a "Both" setting).

In Port Forwarding they need to as follows
Port 5190 to forward to port 5190 (UDP and TCP)
Port 5060 to forward to port 5060 (UDP)
port 5678 to forward to port 5678 (UDP)
Same for the three Rendezvous ports 5297(UDP), 5298 (UDP and TCP) and 5353 (UDP)
Ports 16384-16403 to forward to ports 16384-16403 (UDP)
This last group of 20 ports may be able to be entered in a group as shown but on some routers/modems need to be entered indvidually.
They also need to point to the IP address of your Computer

Ralph

Start of Blog

Hi,

This is the start my Blog. At the moment it is mostly for test purposes. I have not really thought about what will go in here.

Most likely it will be new stuff I find out about iChat.

For those that do not know iChat is an Apple application on Macs that allow Video chatting.

More information can be found from the Index Page

Ralph

The complete set of ports are as follows:
5060, 5190, 5297, 5298, 5353, 5678, 16384-16403

Ralph

Drop down

Drop down
Originally uploaded by Ralph Johns.

Picture of just the Drop Down with entries for iChat

Drop down2

Drop down2
Originally uploaded by Ralph Johns.

Mac Firewall settings with drop down showing.

For iChat.