[erlang-questions] Working around the Windows firewall
Mon Jan 7 18:31:07 CET 2013
On 12/24/2012 01:07 AM, Jeffrey Rennie wrote:
> Before I draft a formal EEP,
> Windows firewall is enabled by default, and blocks sockets used by
> erlang. Yes, exceptions can be added to the firewall, however, this
> is not possible in some situations. For example:
> 1. A corporate network with strict policies that prohibit opening
> ports used by erlang.
> 2. An application written in erlang that installs without
> administrator privileges.
> 3. (A generalization of the above) Whenever the user who wants to run
> erlang is not an administrator.
> In these environments, an alternative to sockets which get entangled
> in the firewall, is Win32 named pipes which do not get entangled in
> the firewall.
> Therefore, I propose a change that will allow erlang nodes to
> communicate over named pipes in addition to sockets. Of course, it
> would be controlled by command-line parameters.
> I've spent a day browsing the erlang source code and it looks pretty
> Comments and questions please.
Good idea! There is actually no need to change anything in the Erlang VM
to do that. The distribution mechanism is pluggable, so you can write a
driver that uses any protocol where you can setup a stream of bytes
between nodes (ok, that sounds easier than it really is, but it's
absolutely doable). There is an example in the kernel source code
($ERL_TOP/lib/kernel/examples/uds_dist) where distribution is set up
using Unix named pipes, which is of course more limited, but shows the
general idea of how to implement a distribution driver.
> P.S. It took me about 5 hours to successfully build on Windows; I had
> most of the tools like Visual Studio and cygwin installed. I got
> tripped up by git switching LFs to CRLFs, which chokes bash. Also,
> it's much faster to just run vcvars32.bat and then run bash than to
> write your own script that sets the vc environment variables.
Yes, it's a pain. The CRLF defaults of msysgit is also a pain. Using
vcvars32 directly may definitely be a shortcut, maybe you could add some
section to the windows readme about your approach?
> erlang-questions mailing list
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