Q: Internet Drops Out Randomly

Okay BD Aqua. Checked out the Console. And I'll access it immediately next time the dropout happens. Let you (and everyone) know what I see/learn. Meanwhile thanks for the suggestion.

Okay, here's the Console dump below.  Dunno what the IPV6 is about, as I have this turned "off" in the TCP/IP pane where I also renew the DHCP lease.  Also dunno about the ProxyList reference as I have all the available proxies un-selected.

Console message:

2/13/13 3:12:41 PM          com.apple.launchd.peruser.501[122]          (com.apple.NetworkDiagnostics[36264]) Check-in of Mach service failed. Already active: com.apple.NetworkDiagnostic.agent

Per System Log:

Feb 13 15:08:01 Macko mDNSResponder[15]: mDNSPlatformUpdateProxyList: IPV6_JOIN_GROUP error -1 errno 47 (Address family not supported by protocol family) group FF02:0000:0000:0000:0000:0001:FFB3:A359 on 4

Feb 13 15:10:01: --- last message repeated 1 time ---

Feb 13 15:12:41 Macko com.apple.launchd.peruser.501[122] (com.apple.NetworkDiagnostics[36264]): Check-in of Mach service failed. Already active: com.apple.NetworkDiagnostic.agent

Feb 13 15:16:28 Macko mDNSResponder[15]: ERROR: send_all(76) wrote -1 of 4 errno 32 (Broken pipe)

Feb 13 15:16:28 Macko mDNSResponder[15]: ERROR: send_all(77) wrote -1 of 4 errno 32 (Broken pipe)

Feb 13 15:16:28 Macko mDNSResponder[15]: ERROR: send_all(78) wrote -1 of 4 errno 32 (Broken pipe)

Feb 13 15:16:28 Macko mDNSResponder[15]: ERROR: send_all(76) wrote -1 of 4 errno 32 (Broken pipe)

ditto, ditto ...

Good suggestion, bad result. Much more frequent dropouts. And because I was in the midst of a deadline thing, I neglected to obtain any Console dumps.  Just restored to iPv6 "off" setting to get my work done. But if you like, I can try this again and obtain the dumps.  Inspite of the lack of success, there may be something to be learned here.

Not sure what you mean by "sharing".  The ISP is Cox in Phoenix.  Everything else on my LAN per above works smoothly, and all through a single router and cable modem to the furnished cable interface in the wall.  Also OS 10.5 works.  It's something with OS 10.6.8 and how it's either different or configured differently -- and in this department I haven't changed anything configuration wise from 10.5, plus I've checked to make sure that my PPC 10.4 machine is also not configured differently (although the Internet setup dialogs are somewhat different and not one-to-one in all the alphabet soup departments, so totally dunno).  Also, Cox want's to send someone out to look at this, but I can't see what they are going to accomplish from a practical standpoint, so I've put them off. IMHO, there's something going on here with my 10.6 upgrade and the way it interfaces with Cox and down stream from them. Note again per above, the ISP indicator never goes yellow, only the final "Internet" and "Server" indicators. Finally, per my travels here and elsewhere on this issue, this problem is sufficiently widespread (97 views above on this thread alone) to warrant some attention from Apple.  Late breaking, just had to renew my DHCP lease again as I tried to post this. 

Thank you for stickiing with me.  I think I've tried something like that, but maybe not with those addresses.  I'll give it a go and report back. I'll label the new alternate location BDAqua in your honor.

Okay BD.  Again it works and it doesn't work. 

It works to the extent that over a relatively long time I did not get any more Internet dropouts on my Intel Mac Pro (the only device on my LAN that was having the dropout problem since upgrading to 10.6). Also interestingly, the new location setup automatically set the iPv6 to "automatic" instead of "off".

And it doesn't work because now my Apple TV streaming device (which heretofore worked perfectly) complained that the DHCP it requires is not functioning, and therefore it can't stream content.  Also when loading internet pages on Safari the progress bar moved in fits and starts under the new location, whereas with the Cox ISP recommended setup the pages load smoothly and quickly (except in the case of a dropout where the load stalls). And finally, Cox doesn't want me to do this for some "it's my own funeral" reason I can't quite remember -- I could ask again.

But perhaps we learned something here?  What do you think?

Okay BD.  I'm giving both these DNS sets a long term trial.  So far no interference with the Apple TV hosted streaming stuff yet -- but we'll see.  So give me a few days before I report back. Also, I'm going to again check with the Cox techs to see what their story is (better to find the el primo Cox techs sometime after the weekend and President's Day break). We now have had 170 views here, so this thread deserves some responsible feedback. Thanks, Bob