Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!

Use iChat A/V features with NAT routers that bind SIP Apps
This is a broader version of a previous hint (Use iChatAV with Speedtouch 510 ADSL modems) about removing the SIP binding from the NAT settings, which will enable iChat's audio and video conferencing features.

This issue also occurs with a lot more routers, not just the SpeedTouch series -- like some (but not all) ZyXel Prestige models. The problem does not always occur, but a sign of this problem is that iChat does not allow the user to set up an audio of video conference. Instead it will list the user as "Busy in another conference" when you try to connect.

Instead of modifying your modem's settings, here's a potentially easier fix. Simply tell iChat to connect using port 80 in its Preferences. Open iChat -> Preferences, click on Accounts, then click on Server Options. Take note, the Server Options button is only enabled when you are not connected to the iChat servers). After changing this setting, iChat will circumvent the SIP binding problems, and audio/video chats should now be possible.
    •    
  • Currently 2.50 / 5
  • 1
  • 2
  • 3
  • 4
  • 5
  (2 votes cast)
 
[12,722 views]  

Use iChat A/V features with NAT routers that bind SIP | 7 comments | Create New Account
Click here to return to the 'Use iChat A/V features with NAT routers that bind SIP' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
Use iChat A/V features with NAT routers that bind SIP
Authored by: yan on Oct 26, '04 11:40:17AM

I think many of the router manufacturers are adding default SIP nat mappings to their newer firmware releases. If you update your router firmware and then ichat AV stops working then this might be the problem. This happened to my cousin when he updated his router firmware.

I wonder if there are any limitations with using port 80 or whether it improves video chat compatibility with people using aim on the PC.



[ Reply to This | # ]
Use iChat A/V features with NAT routers that bind SIP
Authored by: yan.nl on Oct 26, '04 05:44:26PM

Well, it's not connecting here when using port 80 ... :-(

---
Ukraine Spy



[ Reply to This | # ]
Use iChat A/V features with NAT routers that bind SIP
Authored by: jaydisc on Oct 26, '04 11:41:38AM

I thought that port number was the port to login to AOL with..... nothing else.



[ Reply to This | # ]
Use iChat A/V features with NAT routers that bind SIP
Authored by: lullabud on Oct 26, '04 01:17:32PM

I'm with you on this one, Jaydisc. I thought this was only the port to which iChat connected to the AIM service. I just tested this with two mac's on the same LAN and a one-way video conference. I sniffed the packets with tcpdump and saw nothing which indicated that changing the AIM server settings to port 80 would also change the iChatAV ports. This could be a limitation in my test though, since I tried only a successful case. Switching to different port numbers could be a fall-back mechanism...



[ Reply to This | # ]
Use iChat A/V features with NAT routers that bind SIP
Authored by: denty on Oct 26, '04 01:26:23PM

I thought the same too. But I've seen so many times when my friend (who's not exactly computer illiterate) has managed to call me with his port set to 443 (the SSL equivalent of port 80) but not with it set to the default that I think there's something more to it.

Does anyone know actually what goes on in an iChat connection initiation?

I've done quite a few ad hoc packet sniffing exercises but failed to understand it all. I've not really seen any document that would help me say that any particular network configuration would or would not work. There is the iChat ports and firewalling guide from Apple Knowledgebase but it's not enough.

Does it exist?



[ Reply to This | # ]
Use iChat A/V features with NAT routers that bind SIP
Authored by: dreness on Oct 27, '04 01:07:53AM

http://tim.geekheim.de/archive/000145.html

Note that the 'third computer telling each of the peers about the IP addresses that are actually used when sending out UDP packets' in the case of iChat AV is snatmap.mac.com.

andre@pimp[~]defaults read com.apple.iChat | grep snat
snatmap = {ip = "snatmap.mac.com"; port = 5678; };

-andre



[ Reply to This | # ]
Here's a nice tool to help
Authored by: paco on Oct 30, '04 10:00:23PM
Everyone's network is different, so it's useful to have a little tool to help figure out if your network is friendly to iChat A/V. Take a look at this guy's blog about troubleshooting iChat A/V. Look carefully for the link to the disk image and download it. It will help you figure out the NAT mappings that your various routers/firewalls are inflicting on you.

[ Reply to This | # ]