From: Nathaniel Talbott <nathaniel@...>
Date: 2004-01-16T10:07:51+09:00
Subject: Re: drb, firewall, ssh tunneling, and yield

On Jan 15, 2004, at 19:49, Joel VanderWerf wrote:

> Nathaniel Talbott wrote:
>> Is the client side firewalled also? Basically callbacks work by 
>> running a DRb server on the client, which the server then connects 
>> back to. If your client is firewalled, the server won't be able to 
>> connect to your client.
>
> Yes, that's probably it. The client is behind a NAT.

That'd do it.


>> DRbFire might interest you:
>>   http://rubyforge.org/projects/drbfire/
>> It's still very much in development, but it allows bi-directional 
>> communication through a firewall. It's more oriented towards 
>> circumventing client-side firewalls, but in your case I think it 
>> would work fine if you just forwarded the additional port it needs 
>> (your normal DRb port + 1).
>
> That makes sense. But I haven't got the incantation right. On the 
> client side, I do:

Oh, I wasn't very clear. I meant that's what you'd need to do if you 
were using DRbFire. If you're not, you'd need to specify the url to use 
on the client side when you do your DRb.start_service:

     DRb.start_service("druby://localhost:9877")

Otherwise DRb picks any available port, and specifies your actual 
hostname (instead of localhost). Once you do that, this incantation...

> $ ssh -N -L 9876:remote.host:9876 -R 9877:localhost:9877 remote.host

...should work.


> DRbFire sounds great... I'll check it out!

I'm not sure how much of an advantage it would be in your case, since 
you're already using SSH tunneling. I wrote it to avoid having to do 
that myself. It (obviously) can't handle a firewalled server on its 
own; it would still need the ssh tunnel for that.

HTH,


Nathaniel

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