[Kamailio-Devel] [ openser-Patches-2537716 ] working with DNS server unreachable

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Patches item #2537716, was opened at 2009-01-26 13:59
Message generated for change (Comment added) made by henningw
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Category: core
Group: ver devel
>Status: Closed
>Resolution: Accepted
Priority: 5
Private: No
Submitted By: Daniele Zappasodi (zappasodi)
>Assigned to: Henning Westerholt (henningw)
Summary: working with DNS server unreachable

Initial Comment:
When a child process makes a DNS query it remains suspended until it receives the response from the DNS server, so with few DNS requests you can have all the children blocked, while they could serve the requests that don't need the DNS.
When all DNS servers are unreachable it waits for a long period: 3 (NAPTR+SRV+A) * [number of DNS servers * number of retransmissions * time to wait per each retransmission] seconds.
With this small patch, if the NAPTR request fails because the DNS server is unreachable the process doesn't try to make the SRV and the A queries . If all the configured DNS servers are unreachable, the delay becames: 1 (instead of 3, only NAPTR) * [numbers of DNS servers * number of retransmissions * time to wait per each retransmission] seconds.
It doesn't give any help to reduce the delay when at least one of the DNS server responds.

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>Comment By: Henning Westerholt (henningw)
Date: 2009-02-19 10:24

Message:
Thank your for the patch, i applied  it to trunk with some minor changes. I
used the defined constant from errno.h instead of the magic number, and
also changed the log message a big.

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