Unable to connect to Google Talk

[Mark Doliner]

On Mon, Apr 1, 2013 at 9:58 AM, Rich Donnellan <richdonnellan1 at gmail.com> wrote:
> Here are the errors I am receiving.  It has been working for 4 years and
> then a week ago it just stopped connecting.
>
> (12:55:48) proxy: Connecting to alt1.xmpp.l.google.com:5222.
> (12:55:48) proxy: Error connecting to alt1.xmpp.l.google.com:5222
> (Connection timed out.).
> (12:55:48) proxy: Connection attempt failed: Connection timed out.
> (12:55:48) jabber: Unable to connect to server: Connection timed out..
> Trying next SRV record or connecting directly.

And I'm assuming that earlier in the debug log there is a similar
error for xmpp.l.google.com?

Pidgin on your computer isn't able to establish a connection to
alt1.xmpp.l.google.com:5222, but it looks like it isn't able to.
Possible reasons:
- A local software firewall is running on your computer and blocking
outgoing connections to those hosts on port 5222.
- A piece of network equipment between your computer and Google is
blocking connections to those hosts on port 5222.  This could be a
company firewall or content filtering device, for example.
- Your computer, home router, or ISP has broken support for IPv6.
This seems like the most likely cause, to me.  I don't know how long
this has been happening, but the hostnames used for Google Talk return
IPv6 records when doing a DNS query for AAAA records.  Some (most?)
operating systems query for AAAA records by default if your computer
has an IPv6 address.  I'm guessing either Google started returning
AAAA records or your computer started querying for them or your ISP
started giving you an IPv6 address.  I feel like there should be
messages earlier in the debug log that print the IP address that
Pidgin is trying to connect to.  You could try telneting to that on
port 5222 from the command line and see if it works.  You could also
try doing an A looking for xmpp.l.google.com and telnet to that on
port 5222 and see if that works.  To fix this, you could probably just
turn off IPv6 somewhere in your computer's network settings.  This is
unlikely to have harmful side effects, at least for the next year.  If
this is indeed the cause, you should also contact an engineer at your
ISP (not typical front line customer service, because they're usually
clueless) and let them know you're having problems.