[PLUG] More on IPv6 problems

[Bruce Kilpatrick]

I am not sure if I am looking in all the right places, but, my Ubuntu 
(Breezy) Synaptic Package Manager shows no Avahi installed.  Whereis and 
apropos show nothing for avahi either.
Since I am not having problems at this point, it's just a matter of 
discussion and curiosity at this point. 

Bruce

Michael M. wrote:

> I don't know if this will be of any help to anyone else who has had 
> browsing and other connection-related issues due to IPv6 
> misconfiguration problems, but I stumbled across a little discovery 
> quite by accident.  My problems were with Debian and Ubuntu, both the 
> x86 and PPC versions, and the symptoms were that network activity was 
> touch-and-go (usually gone) across a wide variety of functions.  It 
> wasn't *just* Firefox that was broken, but anything that was in some 
> way shape or form IPv6-enabled -- using aptitude or apt to connect to 
> Debian's and Ubuntu's servers, for example, would timeout unless I 
> first pinged the servers; bittorrent would also fail to connect to a 
> tracker unless I first pinged the server hosting the tracker.  These 
> problems unexpectedly and automagically resolved themselves after I 
> installed Arch Linux.  My guess, and it is purely a guess, was that 
> there was some problem with the way Debian and Ubuntu interacted with 
> my modem/router (a Qwest-provided Actiontec GT-701-WG), and that 
> installing Arch somehow reset something in the device.  Upon 
> reinstalling both Debian and Ubuntu (after having installed Arch), all 
> apps worked out-of-the-gate under Debian and Ubuntu -- the same apps 
> that had given me grief before.  It was no longer necessary for me to 
> disable IPv6 in either OS (a fix that was never entirely satisfactory, 
> as I still had residual connection problems).  And just to be clear, 
> under Arch, there was never any problem at all.
>
> What I discovered is that the problem returned under Debian when I 
> installed the gnome metapackage.  I'm not sure how other distros do 
> it, but in Debian there are basically three versions of Gnome:  1) 
> gnome-core, which I think provides the essential libraries and some 
> core gnome apps; 2) gnome-desktop-environment, which provides a 
> reasonably complete Gnome setup without including everything in the 
> Gnome universe; and 3) gnome, which is much of the Gnome universe.  I 
> had had gnome-desktop-environment installed, as per my usual, and 
> decided to install gnome.  Immediately, my IPv6 problems returned.  I 
> promptly uninstalled gnome, leaving gnome-desktop-environment, and the 
> problems went away again.  (Heavy sigh of relief there.)
>
> In looking over what additional apps get installed with gnome, it 
> seems to me the likely candidate for what caused the problem is avahi 
> -- not sure if it's avahi-daemon, avahi-dnsconfd, or avahi-utils, as 
> all get installed with the gnome metapackage and none are installed 
> with gnome-desktop-environment (though I do have some avahi libraries 
> installed).  According to aptitude, for avahi-daemon:
>
> "Avahi is a fully LGPL framework for Multicast DNS Service Discovery. 
> It allows
> programs to publish and discover services and hosts running on a local 
> network
> with no specific configuration.  For example you can plug into a 
> network and
> instantly find printers to print to, files to look at and people to 
> talk to.
>
> "This package contains the Avahi Daemon which represents your machine 
> on the
> network and allows other applications to publish and resolve mDNS/DNS-SD
> records."
>
> For avahi-dnsconfd, the first paragraph is the same; the second reads:
>
> "This tool listens on the network for announced DNS servers and passes 
> them to
> resolvconf so it can use them.  This is very useful on autoconfigured 
> IPv6
> networks."
>
> Sounds to me like that would be something that could muck things up.
>
> I haven't had a chance to read more about what exactly these tools do 
> because of my mom's illness and death, but here's my totally 
> unsophisticated, barely informed pet theory:  at some point in months 
> past, when I was using only Debian and OS X and had only my iMac, I 
> installed the full gnome metapackage on my Debian PPC installation.  
> That dragged avahi in, and reset something in my modem/router that 
> persisted across all subsequent installations of Debian and Ubuntu.  
> Keep in mind that I had these connection issues even during 
> installation -- as often as not, during the installation apt would 
> fail to connect to the servers, and that was with only the base system 
> installed, well before any DE packages were installed or even 
> downloaded.  Whatever avahi did, did not affect OS X, which continued 
> to work fine with IPv6 enabled.  Installing Arch Linux, for reasons 
> that remain a mystery to me, somehow undid what avahi had done, and 
> because I didn't reinstall avahi under any OS, the problem went away.  
> Until, of course, I reinstalled avahi.
>
> Does that sound like something that's in the realm of the possible?  
> Anyone else who's had or has some of these issues might want to look 
> into whether you have or are likely to have had avahi installed.  It's 
> probably just something that crops up with particular hardware and 
> software combinations that are difficult to pinpoint, which I guess 
> would be why it only bites a few of us.  But, man, does it bite -- I 
> was almost ready to give up on Linux altogether.  At least for me, I 
> know what package to avoid like the plague, at least until these 
> issues are resolved.  I don't currently have Ubuntu installed and 
> given recent life events I'm probably not going to mess with it again 
> at least until Dapper is released, so I can't check whether Ubuntu 
> handles avahi differently than Debian.  I don't have Gnome installed 
> under Arch Linux, so I definitely don't have avahi installed there.
>
> So there you are -- hope it helps.
>