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(tramp)Connection types

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Next: Inline methods Up: Configuration

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Enter node , (file) or (file)node

Types of connections made to remote machines.
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There are two basic types of transfer methods, each with its own
advantages and limitations.  Both types of connection make use of a
remote shell access program such as `rsh', `ssh' or `telnet' to connect
to the remote machine.

   This connection is used to perform many of the operations that TRAMP
requires to make the remote file system transparently accessible from
the local machine. It is only when visiting files that the methods
differ.

   Loading or saving a remote file requires that the content of the file
be transfered between the two machines. The content of the file can be
transfered over the same connection used to log in to the remote
machine or the file can be transfered through another connection using
a remote copy program such as `rcp', `scp' or `rsync'.  The former are
called "inline methods", the latter are called "out-of-band methods" or
"external transfer methods" ("external methods" for short).

   The performance of the external transfer methods is generally better
than that of the inline methods, at least for large files.  This is
caused by the need to encode and decode the data when transferring
inline.

   The one exception to this rule are the `scp' based transfer methods.
While these methods do see better performance when actually
transferring files, the overhead of the cryptographic negotiation at
startup may drown out the improvement in file transfer times.

   External transfer methods do require that the remote copy command is
not interactive -- that is, the command does not prompt you for a
password.  If you cannot perform remote copies without a password, you
will need to use an inline transfer method to work with TRAMP.

   A variant of the inline methods are the "multi-hop methods".  These
methods allow you to connect a remote host using a number `hops', each
of which connects to a different host.  This is useful if you are in a
secured network where you need to go through a bastion host to connect
to the outside world.