From: John Stone (
Date: Tue Jun 28 2016 - 09:55:55 CDT

Hi Kevin,
  Beyond what Joao has said, since you're running VMD and NAMD on
the Windows OS, the Windows firewall may block VMD and NAMD from
communicating with each other unless you specifically allow them.
Furthermore, you must allow them to communicate on the specific
network port number that you have selected, 3000 in the example below.
To do this you will need to have administrator access on your machine.

  John Stone

On Tue, Jun 28, 2016 at 08:51:15AM -0500, Joćo Ribeiro KS wrote:
> Dear Kevin,
> you are right. Until VMD connects to NAMD, the "Error connecting to
> localhost on port 3000" message will appear. But once the connection is
> established, another message must appear :
> Info) Connected to same-endian machine
> If this is not the case, please check if you have more than one IMD
> simulation (namd2 proc) running at the same time, which can cause conflicts

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