FAQ: updated and added host with custom IP question

Updated: August 18, 2010 (http://curl.haxx.se/docs/faq.html)

Updated: September 7, 2010 (http://curl.haxx.se/docs/faq.html)

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  3.16 What certificates do I need when I use SSL?

  3.17 How do I list the root dir of an FTP server?

  3.18 Can I use curl to send a POST/PUT and not wait for a response?

  3.19 How do I get HTTP from a host using a specific IP address?

 4. Running Problems

  4.1 Problems connecting to SSL servers.

  as used by numerous applications that include libcurl binaries in their

  distribution packages (like Adobe Acrobat Reader and Google Earth).

  More than 90 known named companies use curl in commercial environments and

  products. More than 100 known named open source projects depend on

  (lib)curl.

  More than a hundred known named companies use curl in commercial

  environments and products and more than a hundred known named open source

  projects depend on (lib)curl.

  In a poll on the curl web site mid-2005, more than 50% of the 300+ answers

  estimated a user base of one million users or more.

    provide this in order to prove that you actually are who you claim to be.

    If the server doesn't require this, you don't need a client certificate.

    A client certificate is always used together with a private key, and the

    private key has a pass phrase that protects it.

  - Server certificate. The server you communicate with has a server

    certificate. You can and should verify this certificate to make sure that

    you are truly talking to the real server and not a server impersonating

  - Certificate Authority certificate ("CA cert"). You often have several CA

    certs in a CA cert bundle that can be used to verify a server certificate

    that was signed by one of the authorities in the bundle. curl comes with a

    default CA cert bundle. You can override the default.

    that was signed by one of the authorities in the bundle. curl does not

    come with a CA cert bundle but most curl installs provide one. You can

    also override the default.

    The server certificate verification process is made by using a Certificate

    Authority certificate ("CA cert") that was used to sign the server

  But you could easily write your own program using libcurl to do such stunts.

  3.19 How do I get HTTP from a host using a specific IP address?

  For example, you may be trying out a web site installation that isn't yet in

  the DNS. Or you have a site using multiple IP addresses for a given host

  name and you want to address a specific one out of the set.

  Set a custom Host: header that identifies the server name you want to reach

  but use the target IP address in the URL:

    curl --header "Host: www.example.com" http://127.0.0.1/

4. Running Problems

  4.9 Curl can't authenticate to the server that requires NTLM?

  This is supported in curl 7.10.6 or later. No earlier curl version knows

  of this magic. Later versions require the OpenSSL, GnuTLS or Microsoft

  Windows libraries to provide this functionality. Using the NSS library

  will not provide NTLM authentication functionality in curl.

  NTLM support requires OpenSSL, GnuTLS, NSS or Microsoft Windows libraries at

  build-time to provide this functionality.

  NTLM is a Microsoft proprietary protocol. Proprietary formats are evil. You

  should not use such ones.