I am testing collapsed_forwarding plugin 
 via ATS 6.2.x branch.

We observed an error "DNS error 2 for [testurl.com]" for cache-miss, when 
remap.config is configured with "collapsed_forwarding" to work alone as a remap 
plugin. We must modify TSRemapDoRemap() in the plugin to "return 
TSREMAP_NO_REMAP" to allow DNS lookup successful. It does not seem right for 
the plugin to do "return TSREMAP_NO_REMAP" when it did not.

Can someone help me to understand how this plugin needs to be used? Or does it 
require the fix I mentioned above?


== Sample remap.config entry and cach miss error when used 
"collapsed_forwarding" by itself ==
map http://testurl.com/ http://origin.com/ @plugin=collapsed_forwarding.so 
@pparam=--delay=10 @pparam=--retries=5

I observed that during cache-miss, DNS query happens on the 'from' url 
(hostname) in the remap and it gets failed.
[Sep  9 19:39:16.355] Server {0x2b170ea6c940} DEBUG: (dns) send query (qtype=1) 
for testurl.com to fd 43
[Sep  9 19:39:16.355] Server {0x2b170ea6c940} DEBUG: (dns) sent qname = 
testurl.com, id = 9287, nameserver = 1
[Sep  9 19:39:16.355] Server {0x2b170ea6c940} DEBUG: (dns) sent_one: 
failover_number for resolve 1 is 1
[Sep  9 19:39:16.628] Server {0x2b170ea6c940} DEBUG: (dns) received packet size 
= 52
[Sep  9 19:39:16.628] Server {0x2b170ea6c940} DEBUG: (dns) round-robin: 
nameserver 1 DNS respons code = 0
[Sep  9 19:39:16.628] Server {0x2b170ea6c940} DEBUG: (dns) received rcode = 2
[Sep  9 19:39:16.628] Server {0x2b170ea6c940} DEBUG: (dns) DNS error 2 for 
[Sep  9 19:39:16.628] Server {0x2b170ea6c940} DEBUG: (dns) doing retry for 

I further looked in to the code and found that it is due to return code from 
the plugin is TSREMAP_DID_REMAP in TSRemapDoRemap(). It makes ATS not to 
perform remap.

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