On Dec 24, 2003, at 2:47 AM, Jacob Swed wrote:

>> "without --disable-ipv6" mean?
> It means when running the Configure script we did not specify the
> --disable-ipv6 option.
>
> Unfortunately, our test servers are internal and our customers are
> accessing Microsoft Exchange with our products so that isn't an option
> either. However, any hostname will do, but a good example is actually
> to pass a non-existent IP address.

Actually, no, that's a terrible example. When you try to connect to a
non-existent (well really, an IP address for which no machine is
accepting network connections), curl goes into a select looping waiting
for either a connection, an internal timeout, or potentially an OS
timeout. One of the timeouts is being hit, which is why it is taking a
long time.

> Here are a couple example, in both cases latest Curl run from the cmd
> line. It was compiled and run on OS 10.2.8. Also, 192.168.1.234 does
> not exist on our network.
>
> With IPv6 Enabled:
> "https://www.frontrange.edu/index.cfm" name lookup took: 1.964 seconds
> "http://192.168.1.234" name lookup took: 22.632 seconds
>
> With IPv6 Disabled:
> "https://www.frontrange.edu/index.cfm" name lookup took: 0.003 seconds
> "http://192.168.1.234" name lookup took: 0.001 seconds

HTTPS connections are bad examples, since overhead from SSL negotiation
(several network round trips and some computation) can obscure test
data. Do you have a non-HTTPS site, and a non-non-existent host that
you can give as an example? I tried "curl -v -I
http://www.frontrange.edu/" with both --disable-ipv6 and not versions
of curl, and the timings were similar (less than a second over a slow
DSL modem)

Also, how are you determining that the name lookup is taking that much
time? For an IP address like "192.168.1.234" I would expect almost no
time taken with the lookup, and a lot of time waiting for the
connection to fail. What is the curl -v output?

Shantonu

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Received on 2003-12-25