[Freeswitch-users] info about sofia sip dns cache and graylisting?

[Michel Brabants]

Hey Brian,

thanks for the reply. I created a new ticket "
https://freeswitch.org/jira/browse/FS-7543" with my take on the issue and
how to resolve it.

Michel

On Fri, May 8, 2015 at 4:38 PM, Brian West <brian at freeswitch.org> wrote:

> can you get some logs, sofia loglevel all 9, and file a JIRA and attach
> the logs and detailed info to the JIRA please.
>
> Also verify which rev of FreeSWITCH you're running when filing the JIRA.
>
> On Fri, May 8, 2015 at 9:34 AM, Michel Brabants <michel.brabants at gmail.com
> > wrote:
>
>> Hello all,
>>
>> we have a problem with a 1.4-version of Freeswitch that FS goes to 100%
>> cpu. The problem has been traced to a dns-cache-problem. The dns-cache
>> contains srv-records, which should have 2 a-records, but they have 100's of
>> a-records, which are mostly the same (some with a different priority). This
>> causes FS do to a lot of compares (to sort the records) and it goes to 100%
>> cpu in the end.
>> The priority almost never is the original priority, so I was thinking
>> that the cache is maybe growing because of graylisting of entries, causing
>> the priority to increase and the ttl to be reset.
>>
>> The code is however very difficult to follow as it is all event-based and
>> part of big C-structs in sofia-sip. A bug in the gdb-debugger causing
>> static variables to be almost unreadable makes life not much easier. The
>> graylisting policy, as well as the dns cache policy is not really
>> documented as far as I can find, so any info about this would be great.
>>
>> Anyway, my current thought is that the dns-cache is maybe growing,
>> becuase the graylisting-code sets the priority to a higher value and resets
>> the ttl to a certain value (no idea which one, but the default is 10
>> minutes and the maximum a day). The srv-record-compare-function however
>> checks also using priority and weight and returns a negative response if
>> they are different. I would think that fs maybe then readds the original
>> srv-records (with priority 0) when it requeries the dns. Those entries will
>> also increase in priority and ttl when they are added, causing the cache to
>> keep growing ...
>> Nscd is also being used for dns-caching, which doesn't help, but I'm not
>> sure if that is the problem as sofia_dig seems to return valid values
>> (except maybe ttl).
>>
>>
>>  I would think that ttl is never touched and that the cached is cleared
>> when the ttl expires, but I have no idea when the dns-cache is cleared in
>> FS...
>>
>> I know this is maybe a lot of text, but any info on this topic (sofia dns
>> cache) is welcome.
>>
>> Thanks,
>>
>> Michel
>>
>>
>>
>>
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com
>>
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org
>> http://confluence.freeswitch.org
>> http://www.cluecon.com
>>
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users at lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org
>>
>
>
>
> --
>
> *Brian West*
> brian at freeswitch.org
>
>
> *Twitter: @FreeSWITCH , @briankwest*
> http://www.freeswitchbook.com
> http://www.freeswitchcookbook.com
>
> ClueCon 2015 Call for Speakers
> <https://www.cluecon.com/call-for-speakers/> | Register
> <https://freeswitch.com/cart.php?gid=1> TODAY! | Reddit: /r/freeswitch
> <https://www.reddit.com/r/freeswitch>
>
> *T:*+19184209001 | *F:*+19184209002 | *M:*+1918424WEST (9378)
> *iNUM:*+883 5100 1420 9001 | *ISN:*410*543 | *Skype:*briankwest
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
>
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20150511/c7dd961c/attachment.html