Curl not working with IPv6 on Windows about curl HOT 12 CLOSED

Hostname for the example is funnel.vtti.vt.edu if you want to test your DNS resolution too.

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The readme for libcurl 7.43 within this package does indicate it is built with --enable-ipv6

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read.table("http://...") gives mixed results; apparently there is some variability there as well. However, on at least some Windows hosts I can test with, I have successfully used read.table where curl fails as described above.

from curl.

Afaik, ipv6 support depends on the operating system. Which windows are you testing on? Can you verify that this problem exists on Windows 10 or Windows server 2008? Also what do you get for:

curl::nslookup("ipv6.test-ipv6.com")

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The systems being used are Windows 7, which otherwise has had excellent
IPv6 compatibility. I have not found a Server 2008 box or Windows 10 near
me that has R installed.

On Thu, Apr 7, 2016 at 1:36 PM, Jeroen Ooms [email protected]
wrote:

Afaik, ipv6 support depends on the operating system. Which windows are you
testing on? Can you verify that this problem exists on Windows 10 or
Windows server 2008?

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#59 (comment)

Clark Gaylord
[email protected]

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Btw read.table("http....") works fine to IPv6 host on the same client.

from curl.

library(curl)
curl::nslookup("funnel.vtti.vt.edu")
[1] "2001:468:c80:a202:0:b074:0:c082"

con=curl("http://funnel.vtti.vt.edu/~cgaylord/x.txt")
readLines(con)
[1] "42"
--- netstat indicates this is using legacy IP

con=curl("http://[2001:468:c80:a202:0:b074:0:c082]/~cgaylord/x.txt")
readLines(con)
Error in readLines(con) : Couldn't resolve host name

read.table("http://funnel.vtti.vt.edu/~cgaylord/x.txt")
V1
1 42
--- netstat indicates this is using IPv6

read.table("http://[2001:468:c80:a202:0:b074:0:c082]/~cgaylord/x.txt")
V1
1 42

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curl::nslookup("ipv6.test-ipv6.com")
[1] "2001:470:1:18::119"

from curl.

On Mac:

con=curl("http://[2001:468:c80:a202::b074:0:c082]/~cgaylord/x.txt")
readLines(con)
[1] "42"

Although, ironically Mac read.table is broken:

read.table("http://[2001:468:c80:a202::b074:0:c082/~cgaylord/x.txt")
Error in file(file, "rt") : cannot open the connection
In addition: Warning message:
In file(file, "rt") : unable to resolve '[2001'

from curl.

I think it is actually a bug in libcurl. Updating libcurl for Windows seems to fix the problem. Can you try to install the new curl:

install.packages("https://github.com/jeroenooms/curl/archive/master.tar.gz", repos = NULL)

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That seems to have done it -- thanks!

con=curl(url="http://[2001:468:c80:a202::b074:0:c082]/~cgaylord/x.txt")
readLines(con)
[1] "42"

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OK I pushed this update to CRAN so it should be available in a day or so.

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