[Techtalk] LinkedIn Ubuntu connection weirdness

[Wim De Smet]

Hi,

On Fri, Apr 9, 2010 at 11:38 PM, Meryll Larkin <mll at alwanza.com> wrote:
> Hey Wim,
>
> It worked and maybe you can tell me how/why??? - because I'm baffled!

Unfortunately I have no idea either. :-)

> I went back to the Coffee Shop and verified that I could not reach any
> second page deep level in LinkedIn.
>
> Then I changed my DNS in resolv.conf to Google's DNS, restarted my
> networking services and behold:  I can now use LinkedIn from the Coffee
> Shop!
>
> The weirdest thing was that I couldn't get a traceroute to anywhere at all
> after I switched DNS to Google - I reached the gateway (192.168.1.1 their
> wireless router, I presume) and that was it.
>
> Here is why I'm baffled:
>  1.  I had already tried different DNS settings from the Coffee Shop
> (although not Google), including the one that my girlfriend was using that
> worked for her (on Windows).
>  2.  The DNS that doesn't work for me to connect to LinkedIn at the Coffee
> Shop is the same DNS that DOES work for me to connect to LinkedIn from home
> (the coffee shop is about 5 miles from home).

Perhaps your DNS server is forcing iterative resolution of the IP and
the connection isn't stable enough or just too slow for you to get
back the results of one of the pieces of this query. Or maybe your
laptop thinks it can do ipv6 but it can't and it's failing in a
non-obvious way. (I noticed linkedin has at least some ipv6 records
for their DNS servers, so you could be trying to resolve through those
and failing). Actually the two combined would explain a lot. Clients
thinking they can do ipv6 when they can't is one major reason for
networks breaking in strange ways.

>  3.  Any why did traceroute stop working???

Seems unrelated, perhaps something about how you changed your configuration.

> These must be very advanced networking mysteries.  Please teach me to point
> me to good documentation!

I think I read the original DNS HOWTO for bind back in the day, but
its last update is from 2001. I'm not sure about any good, current
resources. Though DNS is a somewhat stable protocol.

regards,
Wim