# Solve a problem with remote kernels configuration?

**URL:** <https://community.wolfram.com/t/solve-a-problem-with-remote-kernels-configuration/15530>\
**Category:** Questions\
**Tags:** mathematica, external-interfaces, tuning-and-debugging\
**Created:** [March 19, 2020, 2:32pm UTC](https://community.wolfram.com/t/solve-a-problem-with-remote-kernels-configuration/15530 "2020-03-19T14:32:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mirkosserino](https://yyz1.discourse-cdn.com/wolfram/user_avatar/community.wolfram.com/mirkosserino/32/40761_2.png) [@mirkosserino](https://community.wolfram.com/u/mirkosserino)\
**Post date:** [March 19, 2020, 2:32pm UTC](https://community.wolfram.com/t/solve-a-problem-with-remote-kernels-configuration/15530/1 "2020-03-19T14:32:58Z")

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Hello everybody !

I want Mathematica 12 on my Macbook Pro (“client” in what follows) to connect to Mathematica on a quad core iMac (Personal Use License, named “host” in what follows) to distribute quite a heavy computation across parallel kernels.

1. 

I first thoroughly went through the tutorials on both Lightweight Grid manager as well as remote kernels configuration, but I can’t make either work.  
Lightweight Grid manager works fine on my host: what is recommended to check at

> **[Wolfram Support Quick Answers](https://support.wolfram.com/29206?src=installation-gridmathematica)**
>
> Answers to common Wolfram products questions on installation, activation, purchasing, troubleshooting, upgrading.

was checked, but when my cleitn tries to connnect to the host, RemoteServicesAgents[] does return the IPv6 address of my host but LightWeightGrid would not connect to it.  
I tried to run HostLookup[IPAddress[…]] where the dots stand for the IPv6 address of the host and the function would not find the host;  
thinking that there could be an issue with IPv6 instead of IPv4 addresses, I disables IPv6 addressing on both computers and restarted both systems, but the gridMathematica server would still produce the same IPv6 address and the problem would persist.

1. 

Next, I tried the remote kernel activation, by using the shell command  
**ssh -x -f -l ‘myusername’ 'host.local /Applications/Mathematica.app/Contents/MacOS/wolfram -wstp -linkmode connect tcpip -linkname linkernel -subkernel -noinit \> & /dev/null &**

which fails, returning the error

**SubKernels::Subkernels:: Timeout for subkernels, received 0 out of 4 connections."**  
I extended the time constraint, to no avail.  
Moreoverm when I execute the command above in the cleitn terminal shell, I get the message

**LinkConnect::linkc: – Message text not found – (LinkObject[linkernel, 3, 1])**

Of course the two computers are configured to communicate through a private/public ssh key pair and I have tested this separately in advance on the terminal and it works juts fine.

(Maybe) a hint: when I try to use URLRead[“host.lan”], URLRead would fail to connect, even if I supplement it with Usernae and Password.

Any help would be greatly appreciated.

Mirko

 ![Grid-1.jpg](https://global.discourse-cdn.com/wolfram/original/3X/3/0/30c2f1e908706c0ef3391952c24ab1e79df92502.jpeg)

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**Author:** ![juanlizarazoferro](https://avatars.discourse-cdn.com/v4/letter/j/bcef8e/32.png) [@juanlizarazoferro](https://community.wolfram.com/u/juanlizarazoferro)\
**Post date:** [April 27, 2020, 10:20pm UTC](https://community.wolfram.com/t/solve-a-problem-with-remote-kernels-configuration/15530/2 "2020-04-27T22:20:39Z")

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I’m having a similar error in a different scenario for launching remote kernels. Did you figure it out?

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**Author:** ![mirkosserino](https://yyz1.discourse-cdn.com/wolfram/user_avatar/community.wolfram.com/mirkosserino/32/40761_2.png) [@mirkosserino](https://community.wolfram.com/u/mirkosserino)\
**Post date:** [April 28, 2020, 9:19am UTC](https://community.wolfram.com/t/solve-a-problem-with-remote-kernels-configuration/15530/3 "2020-04-28T09:19:49Z")

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Hi Juan,  
yes I did, somehow: eventually I installed the update of Mathematica restarted my computer and WolframLightweight Grid started to work. I did not try anymore to invoke the remote kernels with the functionality available through the Remote Kernel window.

Best,  
Mirko