Re: [reSIProcate] DNS SRV multiple records and timeouts

[Nathan Stratton <nathan@xxxxxxxxxxxx>]

On Thu, Aug 15, 2013 at 11:38 AM, Scott Godin <sgodin@xxxxxxxxxxxxxxx> wrote:

Hi Nathan,

As you mentioned grey listed items will only be tried when all other non-blacklisted results are checked.  This means we will not try the grey record first.  So new requests should be using the non-greylisted and non-blacklisted entries.

Some additional points:

1.  Records are only greylisted for 32 seconds.  So after that time expires, we could end up trying the potentially bad record again, and repeating the greylist process.  Making the greylist time configurable would be nice.

2.  If you are creating a client and don't need to load balance your outbound requests, then you could enable Whitelisting support - this enable get your client to stick to a good record tree when one is found.  This is disabled by default, since it breaks load balancing in SIP server applications.  See  http://www.resiprocate.org/DNS for more info on how to enable whitelisting (a compile time flag).

Yes, we could whitelist, but that would require knowing all the hosts upfront. We could have our gateway add timeouts to the blacklist, but as I was thinking about it I was just wondering why they were gray and not black. Why would you want to continue to try a host that you know will timeout? 

--

><>
Nathan Stratton                                               Founder, CTO Exario Networks, Inc.
nathan at robotics.net                                     nathan at exarionetworks.com

http://www.robotics.net                                   http://www.exarionetworks.com/