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From: Steve Wilson on 6 Feb 2007 02:52

On Feb 5, 2007, at 1:34 PM, T.Sariyski wrote:

> I have a wireless (disabled) and an ethernet port. I don't get any
> dialog box except "Low-level MathLink error: Unknown internal
> error. ". To avoid a silly mistake from my side here is what I do:
> 1. On Kernel Configuration Options I set:
> MLOpen: -LinkMode Listen -LinkProtocol TCPIP -LinkHost
> 192.168.187.99
> Shell command: ssh tsariysk(a)192.168.187.99 math -mathlink -
> LinkMode Connect -LinkProtocol TCPIP -LinkName `linkname`
>

> Ethernet adapter Local Area Connection:
>
> Connection-specific DNS Suffix . : craft-tech.com
> Description . . . . . . . . . . . : Broadcom 440x 10/100
> Integrated Controller
> Physical Address. . . . . . . . . : 00-0D-56-EA-59-98
> Dhcp Enabled. . . . . . . . . . . : Yes
> Autoconfiguration Enabled . . . . : Yes
> IP Address. . . . . . . . . . . . : 192.168.187.232
> Subnet Mask . . . . . . . . . . . : 255.255.255.0
> Default Gateway . . . . . . . . . : 192.168.187.1
> DHCP Server . . . . . . . . . . . : 192.168.187.248
> DNS Servers . . . . . . . . . . . : 192.168.187.150
> 192.168.187.20
> Lease Obtained. . . . . . . . . . : Monday, February 05,
> 2007 2:38:03 PM
> Lease Expires . . . . . . . . . . : Monday, February 05,
> 2007 4:18:03 PM


I see the problem. I had you using -LinkHost incorrectly. Change
the MLOpen line to:

-LinkMode Listen -LinkProtocol TCPIP -LinkOptions MLDontInteract


With the MLOpen arguments, -LinkHost tells MathLink to create a link
on the listed interface. 192.168.187.99 is not an interface on your
Windows system. If you want to use -LinkHost with the MLOpen
argument, you have to be sure to use an actual ip number (or domain
name) for an interface on your system (in this case
192.168.187.232). When you use the -LinkHost option with the Shell
command, you are telling the remote process to connect to a link at
the listed ip number (or domain name). So in effect the first time
you ran this set up you were telling the remote Kernel to try and
connect to a link at its own IP number. In general -LinkHost should
not be used unless you have a good reason. It overrides the default
ip number or domain name that MathLink generates when it
automatically creates linknames. LinkHost is useful when you have
multiple interfaces on a machine and want MathLink to bind to a
particular interface without affecting any of the other interfaces.
LinkHost can also be useful if you have firewalls, routers, or other
kinds of network devices or setups that cause a bit of trickiness
with ip numbers between two machines. If you don't have any of those
conditions on your network, it is better to leave -LinkHost unused.

One further note. You can also specify the interface to use by
giving the interface in the -LinkName option for the MLOpen
arguments. Your original example could have been:

MLOpen:

-LinkMode Listen -LinkProtocol TCPIP -LinkName 3500(a)192.168.187.232

Shell Command:

ssh tsariysk(a)192.168.187.99 math -mathlink -LinkMode Connect -
LinkProtocol TCPIP -LinkName `linkname`



I should have seen this at first. My apologies for taking so long.

Steve


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