So, you may or may not remember that I was afflicted with this pain in the neck of a problem: namely, you launch iChat, it loads for a second, and then dies immediately. In trying to solve it, I funted my computer, and needed to reinstall.

Last night, my computer ran out of battery (at the 51% mark, no less – let’s hope this battery holds out), and didn’t sleep, so I gave it a hard reset and thought nothing more.

This morning, I realise I haven’t relaunched iChat – so I do – and it dies immediately. “Bugger,” I think, “this is the same problem as before”. It’s also the same problem my girlfriend’s iBook has.

Then, thanks to this helpful Apple Discussions post, I solved it. The issue is between the iChat in 10.4.3 and my Netgear DG834 wireless router – namely, the implentation of UPnP (Universal Plug n Play) in the Netgear box. My router, incidentally, is on firmware 3.0.something – the latest.

To get iChat working again: log into the router, scroll down the left hand menu and choose the UPnP menu. Then: untick the “enable UPnP” box, click Apply; re-enable it, click Apply.

iChat now works. Bizarre, but fortunately solved. It’s also apparently fixed in 10.4.4, released yesterday, but I’m not upgrading just yet due to being bitten on 10.4.3.

25 comments on this entry.

  • James Harvard | 3 Apr 2006

    Just wanted to say thanks for posting this – Googled up this page after having the same problem with iChat and a Netgear router. I can confirm that the solution outlined above fixes the problem immediately.

  • Tom | 3 Apr 2006

    You’re welcome, James; it’s a complete pain-in-the-neck of a problem, and the solution is rather illogical. Glad it worked for you.

  • Max | 18 Aug 2006

    Brilliant! This post saved me a possibly expensive call to Netgear Tech Support. I am using the DG834G and OS 10.3.9. Thanks.

  • blake bozeman | 9 Nov 2006

    I tried this and it didn’t work for me. If anyone else can’t get this to work try turning off the SPI firewall under the WAN setup options. works like a charm now.

  • Paula | 25 Nov 2006

    THANK YOU SO MUCH. I’ve been looking for the answer everywhere and I found it on here!

  • Dave | 15 Dec 2006

    This didn’t work for me. However, two other methods seem to work fine.

    First method – change the port iChat uses from 5090 to 5091 in the iChat server preferences. That works best for me.

    Another method I found was to add a service in port triggering for iChat. The trigger port is 5678 UDP and it triggers port 5060 TCP/UDP.

  • Dave | 15 Dec 2006

    Correction. That should be “port 5190 to 5191”. Sorry for the mistake.

  • mrclaassen | 26 Dec 2006

    Thanks man, changing the port in iChat did the trick and saved many more hours of searching.

  • Paul | 8 Jan 2007

    I tried disabling UPnP on a Netgear WGR614v6, didn’t work. Also had to disable the SPI Firewall (UPnP may have been fine, I didn’t bother to check with SPI off). Thanks for the tips!

  • walt | 23 Jan 2007

    Changing port to 5191 seemed to fix this problem for me. Macbook Pro. OSX 10.4.8. Still some video issues but no crash at start…

  • Sinewave | 22 Mar 2007

    I have a WGT624v3 (Firmware V2.0.10_1.0.1) and am pleased to report that changing to port 5191 did the trick, as did disabling the SPI firewall (which i promptly enabled again when i discovered the former worked ok). (iChat on a MacBook OS X 10.4.9). Thanks people!

  • Caroline | 30 Jul 2007

    I am not using a Netgear router, but was having the same issue: “The connection to the host was unexpectedly lost.”. Changing the port to 5091 did the trick.

    Powerbook & Macbook pro on 10.4.10

  • prasanthi | 25 Oct 2007

    hey, does this happen with the belkin n1 wireless router?

    how do i change the ports, anyways? (if ichat isnt opening for me at all)

  • Judy | 15 Nov 2007

    THANK GOODNESS for the post re: changing the port to 5091! I’ve been attempting to solve this problem for HOURS. The Apple tech support guy was of absolutely NO help whatsoever.


  • DJ | 12 Jan 2008

    Well, it wasn’t really this article that helped me but the comments. As soon as i changed the port form 5190 to 5191 it worked great. Thanks to all.

  • audia2000 | 16 Jan 2008

    Thank you so very much!
    I changed ichat’s port to 5191 and now it works with my Netgear WGR614.

    And now for something completely different…

    When I use “DropShare” to share files directly from my computer, it only works when I’m on the cable – not via Netgear WGR614 WLAN router. Any ideas why? Is the re something I can change on the router?

    Thanks for any hint.

  • Marc James | 22 Feb 2008

    WOW THANKS FOR THE COMMENTS!!!!!!!!!!!!!! I’ve been killing myself trying to find out how to fix this problem that i’ve had. and changing 5090 to 5091 did the trick!!!!! I VERY MUCH APPRECIATE IT!!!!!

  • Dan | 22 Feb 2008

    This one worked for me! Thanks:

    “change the port from 5190 to 5191”

    the Port is under “Prefs” and then “Accounts”

  • Dan | 10 May 2008

    Ive been having this problem on a brand new macbook.

    I tried changing my router settings, it seems to be working.

    Lets hope it stays.

    Thanks for all these comments

  • Derrick | 14 Jun 2008

    I just got a brand new Netgear wireless N router and have OS 10.5.2



  • Derrick | 15 Jun 2008


    Actually still having issues, this resolution doesn’t work well if you have more than one comp on your network, because it seems to only work for one at a time.

  • Derrick | 15 Jun 2008

    Update Again:

    This will fix the problem for all computers on the network:

    Apple iChat / Netgear router issue

    This is an issue I had with iChat and my Netgear WTG624 v3 and it took me a while to understand how to fix it.

    First, let me give you an overview of the problem. What happened was I got my Netgear router, hooked it up and started using it and everything seemed fined. Well, my wife works from home occasionally and connects to her office via VPN. She went to try this and it wouldn’t connect so I started looking around the router settings. I finally decided it was because the SPI firewall was disabled (I don’t know the actual reason, but enabling this seemed to fix it). Then I noticed that once this was enabled, my iChat wouldn’t connect to the AIM server. All other protocols were working within iChat, but AIM wasn’t. I then tried a different mac AIM client and that seemed to work correctly. I was also able to connect to AIM using Trillian on my pc so obviously it was something with iChat. Well, I googled around for a bit and didn’t come up with much so for a few months we just dealt with enabling / disabling the SPI firewall within the router everytime she wanted to connect to her VPN.

    I finally got sick of doing this so I started looking around. It turns out that all you need to do is change your port in your iChat settings. Here are the specific instructions I found at Appleinsider.

    1. Go to Ichat/preferences.
    2. Click on accounts, then click on server settings.
    3. Then put in 443 as the Port.
    4. Done. (don’t check connect using proxy)

    Hopefully this helps someone else.. I know it was a pain in my ass for a while.

  • Jen | 18 Oct 2008

    As Judy before me said, the 90 to 91 in the port iChat uses did the trick! This is super! I’ve my macbook for over a year and never got to use iChat!!!!

  • Sergei Evans | 5 Dec 2009

    So my ichat has been having issues it for some reason won’t work i can’t add any friends it won’t show that my friends are on and i can’t VC nor chat with them. but when i deleted ichat and reinstalled it, it started working again for like 10 maybe even 15 seconds and the same problem comes up.

  • Kat | 27 Feb 2010

    Dave, thanks for the tip, changing the ichat server port setting fixed the problem in seconds!