XMPP and ADSL modem-router problem

[Mark Doliner]

On Sun, Aug 1, 2010 at 9:20 AM, Vangelis Katsikaros <ibob17 at yahoo.gr> wrote:
> On 07/06/2010 08:29 PM, Vangelis Katsikaros wrote:
>>
>> Ethan Blanton wrote:
>>>
>>> Vangelis Katsikaros spake unto us the following wisdom:
>>>>
>>>> I have Pidgin 2.6.2 (libpurple 2.6.2) on ubuntu 9.10. My ISP gave me a
>>>> new ADSL modem-router [1] and since I have the following.
>>>>
>>>> 1) I have the XMPP (jabber) account disabled.
>>>> 2) I enable it and I get the following debug info [2].
>>>> 3) somewhere at (14:42:29) the router freezes completely. It freezes so
>>>> badly that I can't log into it, even if I unplug/replug the ethernet
>>>> cables. The only option to make it work again is to close it and open it
>>>> again.
>>>
>>>> (14:42:29) dnssrv: querying SRV record for gristle.org:
>>>> _xmpp-client._tcp.gristle.org
>>>> (14:42:29) dnssrv: res_query returned an error
>>>
>>> This is almost certainly the cause of both your account not working,
>>> and 3). Your router is proxying DNS, and does not understand DNS SRV.
>>> This is an unfortunately common problem, although one which has become
>>> less prevalent in the past couple of years.
>>
>
> Hi and sorry for bouncing this thread. I am trying to figure out whether my
> modem-router has issues with DNS in general, or there is a specific issue
> with the jabber server I connect to.

Based on the information you've given us it doesn't look like it's
specific to the jabber server you connect to.  The debug log you sent
in your first email shows that Pidgin does not attempt any
connection--it ONLY does DNS lookups.  So XMPP and TCP aren't the
problem.  DNS is the problem.  And the fact that your router hangs is
absolutely a bug in the router.  Have you contacted your ISP yet?
It's really their responsibility to provide you something that isn't
broken.

> --------------------------------------------
> To check the DNS SRV, I try the following:
>
> $ host -t SRV _xmpp-client._tcp.gmail.com
> _xmpp-client._tcp.gmail.com has SRV record 20 0 5222 talk1.l.google.com.
> _xmpp-client._tcp.gmail.com has SRV record 20 0 5222 talk2.l.google.com.
> _xmpp-client._tcp.gmail.com has SRV record 5 0 5222 talk.l.google.com.
> _xmpp-client._tcp.gmail.com has SRV record 20 0 5222 talk3.l.google.com.
> _xmpp-client._tcp.gmail.com has SRV record 20 0 5222 talk4.l.google.com.
>
> $ host -t SRV _xmpp-client._tcp.jabber.org
> _xmpp-client._tcp.jabber.org has SRV record 30 30 5222 hermes.jabber.org.
>
> $ host -t SRV _xmpp-client._tcp.gristle.org
> Host _xmpp-client._tcp.gristle.org not found: 3(NXDOMAIN)
>
> I get the same results using google's DNS (8.8.8.8)
>
> The 1st, 2nd result looks good, the last not so good. I am not much into
> network stuff, so I don't know how to interpret this info
> correctly.
>
> In both cases router does not freak out.

It's possible that DNS SRV records from Pidgin are slightly different
than the ones from these commands, and maybe your router only breaks
when it sees Pidgin's DNS SRV requests.

It doesn't look like the domain gristle.org has a DNS SRV record for
XMPP.  That's not necessarily bad--it just means that clients will
expect to connect to gristle.org on port 5222.

--Mark