title: Cannot install_github in R (Installation failed : name lookup timeout)
body: <p>I have R installed in a Slackware server. When I tried to install rCharts package via github, I got following error:
  <a href="https://i.stack.imgur.com/R0T77.png" rel="nofollow noreferrer">error message</a></p>
  <blockquote>
  <p>devtools::install_github('ramnathv/rCharts@dev')
  Downloading GitHub repo ramnathv/rCharts@dev from URL <a href="https://api.github.com/repos/ramnathv/rCharts/zipball/dev" rel="nofollow noreferrer">https://api.github.com/repos/ramnathv/rCharts/zipball/dev</a>
  Installation failed: name lookup timed out</p>
  </blockquote>
  <p>I have Rstudio running on my windows laptop as well. It worked just fine when I tried to install the rCharts package. The difference I noticed that in my laptop, it takes much time, maybe 4-5 minutes, to connect to the URL address before it begin to install the package, while in the Slackware server, it takes less than a minute trying to connect the URL address before the error message showed up.</p>
  <p>Maybe is it related to curl? Since I have searched the &quot;name lookup timed out&quot; phrase, many results showed up that it is the curl problem.</p>
  <p>Here is the devtools::session_info():</p>
  <pre><code>&gt; devtools::session_info()
  Session info ------------------------------------------------------------------
   setting  value
   version  R version 3.3.3 (2017-03-06)
   system   i586, linux-gnu
   ui       X11
   language (EN)
   collate  C
   tz       &lt;NA&gt;
   date     2018-03-20
  Packages ----------------------------------------------------------------------
   package   * version date       source
   base      * 3.3.3   2017-12-20 local
   datasets  * 3.3.3   2017-12-20 local
   devtools    1.13.5  2018-02-18 CRAN (R 3.3.3)
   digest      0.6.13  2017-12-14 CRAN (R 3.3.3)
   graphics  * 3.3.3   2017-12-20 local
   grDevices * 3.3.3   2017-12-20 local
   memoise     1.1.0   2017-04-21 CRAN (R 3.3.3)
   methods   * 3.3.3   2017-12-20 local
   stats     * 3.3.3   2017-12-20 local
   utils     * 3.3.3   2017-12-20 local
   withr       2.1.1   2017-12-19 CRAN (R 3.3.3)
  </code></pre>