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From Greg O'Rawe <Greg.O'>
Subject RE: ATS without DNS
Date Tue, 10 Mar 2015 16:13:57 GMT
Thanks for the reply.

Yes, this is an old version of ATS – we are in the process of upgrading to 5.0 but this
is not released yet and the version deployed on customer sites is still 3.2.0.

Enabling the first parameter<>_origin_server_dns
along with proxy.config.http.no_dns_just_forward_to_parent appears to work (the first parameter
does not appear to be documented though). DNS lookups and the failover processing are bypassed
and warning message is not logged. Requests get a “502 Next Hop Connection Failed” response.


From: Leif Hedstrom []
Sent: 09 March 2015 18:11
To:; Greg O'Rawe
Subject: Re: ATS without DNS

On Mar 9, 2015, at 10:44 AM, Greg O'Rawe <Greg.O'<mailto:Greg.O'>>


I have a deployment of ATS 3.2.0 as a forward proxy where there is no access to DNS (no nameserver
entry in the /etc/resolv.conf file). The origin server IP address is normally supplied by
a request header which calls the API to set the target address but in some cases the header
is not present. The setup is not transparent so the client destination IP address is that
of the ATS and so can’t be used, resulting in DNS lookups.

First, that’s a really old version of ATS, one that is EOLifed already. You should consider
upgrading to an LTS version.

That much said, there are a few options to examine:

  <>_origin_server_dns  (0
by default)
            proxy.config.dns.failover_number  (5 by default)
            proxy.config.dns.lookup_timeout (20 by default)

There are a few others that might be related. Also, i thought we had a Jira about not successfully
being able to use that first setting, but I can’t find it. Try it, and see what happens.

— Leif

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