Re: [sipX-dev] DNS query problem
>On Sun, 2007-04-15 at 14:49 +0800, tonyxiao wrote:
>> I think there is a lot of way to cause this problem:
>>
>> In a dial plan, I configure that all calls with prefix 0 will forward to
>> sip.mydomian.com.
>>
>> So the authserver, before forwarding the message(the request URI is like
>> INVITE sip:082558998@xxxxxxxxxxxxxxxx), it must perform a DNS query to get
>> the IP address of sip.mydomain.com. This can be failed, the reason may be
>> that no entry for this domain in DNS server ,or the server is down for that
>> moment.
>>
>> This can cause the SipSrvLookup::servers() spend over one minute to return.
>
>There's something else wrong i the query takes that long, even if it
>will eventually fail.
>
>First off, I'd suggest that you put a cache-only DNS server on the same
>system, and change /etc/resolv.conf to point to that server.
The cache-only DNS can't solve this matter. Cause it can only cache a valid
result of query. But a failed query does cost over one minute. Because
SipSrvLookup::servers() will perform 3 times of SRV query and one time of A
query.
tonyxiao
quest1222@xxxxxxxx
2007-04-16
