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The gpfdists protocol is a secure version of gpfdist. gpfdists enables encrypted communication and secure identification of the file server and the Greenplum Database to protect against attacks such as eavesdropping and man-in-the-middle attacks.
gpfdists implements SSL security in a client/server scheme as follows.
- Client certificates are required.
- Multilingual certificates are not supported.
- A Certificate Revocation List (CRL) is not supported.
- The TLSv1 protocol is used with the TLS_RSA_WITH_AES_128_CBC_SHA encryption algorithm.
- SSL parameters cannot be changed.
- SSL renegotiation is supported.
- The SSL ignore host mismatch parameter is set to false.
- Private keys containing a passphrase are not supported for the gpfdist file server (server.key) and for the Greenplum Database (client.key).
- Issuing certificates that are appropriate for the operating system in use is the user's responsibility. Generally, converting certificates as shown in https://www.sslshopper.com/ssl-converter.html is supported.
Use one of the following methods to invoke the gpfdists protocol.
- Run gpfdist with the --ssl option and then use the gpfdists protocol in the LOCATION clause of a CREATE EXTERNAL TABLE statement.
- Use a YAML Control File with the SSL option set to true and run gpload. Running gpload starts the gpfdist server with the --ssl option, then uses the gpfdists protocol.
gpfdists requires that the following client certificates reside in the $PGDATA/gpfdists directory on each segment.
- The client certificate file, client.crt
- The client private key file, client.key
- The trusted certificate authorities, root.crt
For an example of loading data into an external table securely, see Example 3—Multiple gpfdists instances.