Brian Mitchell wrote:
> On 10/4/06, Alex Fenton <alex / deleteme.pressure.to> wrote:
>> Hi
>>
>> I'd like to use druby, but with the client using just an IP address to 
>> contact the server, and vice versa. The initial connection works fine, 
>> but then it seems the server can't find the client to send a reply 
>> when a method is invoked.
>>
>> I realise this question has been asked before, and answered by 'fix 
>> your DNS' or 'tweak etc/hosts'.
>>
>> However, this is for an end-user app, so most users (of clients and 
>> servers) won't be permitted to access etc/hosts, even if I wanted to 
>> explain what they should do to it.
>>
>> So
>> - has anyone hacked drb to work without hostnames?
>> - failing that, is there a deep technical reason that using IP 
>> addresses only will never work and I shouldn't bother even trying? It 
>> seems lots of other net applications work fine without caring that DNS 
>> is fixed, but I've not got masses of experience with socket 
>> programming in Ruby.

> Note that it is a good idea to specify an explicit interface on the
> client side so you make sure it binds to something the server can
> reach. Some systems will bind to something like 127.0.0.1 when
> resolving the host's name (i.e. Ubuntu does this). The two way channel
> is vital to have DRb work reliably in most cases (unmarshalled objects
> can be referenced in both directions).

Adding to that: it might well be that you are trying to do things in 
environments that simply won't permit this.  If your client is behind a 
firewall / router with NAT and the server tries to open a connection to 
the client system that's often not permitted.  So, in order to get this 
to work in these environments someone must actually change FW config.

Kind regards

	robert