kichat: FAQ 6 Interpreting the iChat Connection Doctor

by: Ralph-Johns-UK

Last modified: Nov 15, 2024 8:59 AM

0 798 Last modified Nov 15, 2024 8:59 AM

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Interpreting the Connection Doctor Messages

For iChat version 2.1

Edit 15th Nov 2024 to correct Links at the bottom of the peice

Interpreting the Connection Doctor Messages

For iChat version 2.1

This FAQ is designed for those of you having some problems connecting to your Buddies and getting error messages in the Connection Doctor.

The Connection Doctor is found in the Video or Audio menu in iChat. Which label this Menu has to the right of the Buddies one depends on whether you have a camera or not.

The window extends on a chat failure and can give you useful information if you know how to use it.

Format

2005-03-08 18:34:32 +0000: xxx did not respond. Tried to send UDP SIP "invite" to the following IP addresses and ports:

136.xxx.xxx.xxx:5060 192.168.0.2:5060

This has been altered by the use of xxxes to hide the name of the iChat account in the first line and the full public IP address in the last. The Computer's internal LAN IP address can vary depending on the modem or router used. I will explain more on this later.

It is the last line that is important. The details are of the person at the other end.

Error messages (in no particular order)

136.xxx.xxx.xxx:5060

This can mean:

1) The Buddy is on Dial-up and either is suffering from speed problems or has not got the last group of 20 ports open (16384-16403)

2) The Buddy is on DSL and has not got the last group of 20 ports open.

3) The Buddy has an SIP aware modem. This uses the SIP protocol, as does iChat, on port 5060, as does iChat, and looks for an internet phone (IP phone/VoIP service)

136.xxx.xxx.xxx:15640 192.168.0.2:5060

This can mean:

1) The Buddy has two or more routers and modems in their link to the internet and is using NAT or Port Forwarding in both. iChat does not like a Double NAT situation and the port on the Public IP address gets moved to a non iChat one. Can happen if the ISP also uses NAT on the connection.

2) It can mean that a similar problem is at your end and you are sending data out on the 'wrong' port.

The solution is to make sure only one device is performing NAT. I also would link Port Forwarding in here because of the many routers/modems that NAT when they Port Forward.

136.xxx.xxx.xxx:5060 10.0.1.2:5060

This is a variation on the above. It is easier to predict that there are two devices doing NAT as an IP starting 10.0.1.xxx is going to involve an Airport device. By default these "Distribute Addresses" (Act as A DHCP server) and NAT dynamically (no set up ports).

To test for both these scenarios the user should leave his current System Preferences > Network pane settings to DHCP and connect to each device in turn. If his/her IP address changes then both are acting as a DHCP server and will warrant further investigation to find out if Port Forwarding and or NAT are also being used.

The solution is a question of you deciding which device is going to be the DHCP server and turning it off in the other device. Having two devices acting as DHCP severs creates Subnets and iChat can Text chat like this but not AV chat

In the case of the Airport situation it can be done like this:

Open Airport Admin Utility (Applications/Utilities)

Click on the name of the Airport device in the first (small) window.

Click on Network in next window.

Deselect "Distribute Addresses" and NAT options.

This will let the modem give out IP addresses to all computers and routers on the local network and not cause Subnets.

Alternatively in the case of the Modem being the non issuing device: (The one not doing DHCP and NAT or Port Forwarding)

Turn off NAT/Port Forwarding and give the second device a static IP address by turning off DHCP. In the second device you will probably have to state the Static IP address being used.

192.168.xxx.xxx:5060 or 10.xxx.xxx.xxx:5060 or 172.xxx.xxx.xxx:5060

Note: This is designed to show the groups from LANs created by Modems and Routers. Your error message is likely to contain only one number that is repeated as your computer is seen multiple times.

Also the LAN group 172. should continue with a number between 16 and 32 at the second point to be a LAN IP address

This means:

1) The Buddy has a local network problem. Normally they have both an Ethernet and Wireless connection to the internet. This is particularly true if a Internal IP address form one of the three groups listed above are repeated after a Public one. Symptoms can include double entries in Text chats.

2) They could have their computer set up to Share the Internet Connection and their second computer is also being seen. This can display the same Double messages in Text chats if the second computer is also logged into the AIM servers with the same chat account name.

Useful info

http://www.portforward.com/routers.htm Site detailing Port Forwarding modems and routers with pictures of set up pages. (Edit 2024:- The site no longer has Port Triggering Pages)

Apple Doc 93208 on ports needed. (Edit 2024:- Grabbed from the Way Back Machine)

FAQ 2 kichat: "How can I get my router to work with iChat?" (Edit 2024:- At present I can't find this)

Page 11 on my site may help in the mean time (Edit 2024:- Added but also being updated itself)

page3.html on my Web site My homePages. Also read page 4 (Edit 2024:- Changed link to the "new" Location as I have not updated these FAQs in a while)

Summary

The Connection Doctor reports Connections errors of failed Audio or Video chats.

It shows your Buddy's details.

It displays the IP address given to your Buddy by their ISP (Public IP address) followed by the port the data is arriving on. This is then followed by a second IP from the modem or router and should be in a LAN group (Scroll down to Table B-4). This is again followed by the port number that it is passing the data to their computer on.

IF the Public port does not have port 5060 listed then it is most likely a NAT problem.

If the LAN address does not show up, then the person is either on Dial-up and or does not have the group of 20 ports open (16384-16403).

Repeated LAN IP addresses is normally a computer or iChat name logged on twice or LAN set up problems.

Post any questions to Discussions Mac OS and Earlier OS

Hope this helps.

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