curl 'name look up timeout' error

hi,

I use curl_exec in php to get some date from a url like '
http://abc.com/page/1' on an linux server.

abc.com is not exists, I set it in /etc/hosts like '123.23.2.3 abc.com', I
can ping this hostname correctly, and never lost any ping package.

But when I use curl_exec in php, randomly got error like this mail title
said. The error code is 6.

Then I try to use curl in command line like 'curl http://abc.com/page/1',
the same error randomly occur.

The curl version on that server is curl-devel-7.15.5-2.el5 and
curl-7.15.5-2.el5. I've tried download and compile a curl by hand, and the
error still there.

Why does this happen? Any response would be welcome. thx.

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