On Fri, 28 Jan 2011, Pavel Gushcha wrote:

> I wrote application using curl_multi. This application must fetch each
> second some fixed url, but each time from different ip (i have 20 ip on my
> server). Firstly, i wrote application without requirement to use different
> IPs and all works good. Then i added option to each curl easy handle before
> adding it to curl_multi:
>
> curl_easy_setopt(easy_handle,CURLOPT_INTERFACE,<next ip>)
>
> And i expected, that this is all, what needed. But really ip was not
> changing each request. It was changed around each 20 requests. After problem
> exploration i figured out, that adding following option to easy handle fixes
> the problem:
>
> curl_easy_setopt(easy_handle,CURLOPT_FORBID_REUSE,1)

You've fallen into the same trap/bug/glitch that someone else did a short
while ago with pipelining and CURLOPT_INTERFACE: libcurl doesn't check the
desired source ip/port when it searches for a connection to re-use but is
happy if it targets the correct destination host.

This is a bug that should be fixed, and since you have a use-case here it
would be great if you could look into this.

The function that takes care of finding a connection to re-use is
lib/url.c:ConnectionExists().

> PS: sorry for my bad english.

No problems at all, we can understand you perfectly!

-- 
  / daniel.haxx.se
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