[vbox-dev] Issue with 127 network

[Klaus Espenlaub]

On 10.01.2013 19:08, manvi singh wrote:
> Klaus - Thanks for the response. The assigned IP address would be
> something like 127.3.252.1. And i hadnt tweaked anything on the host or
> VB to get this working.

Please stay on the mailing list, otherwise I'll ignore further mails. I 
can't offer personal consulting.

It doesn't make any sense to me. Each and every 127.0.0.0/8 address in a 
properly set up TCP stack is equivalent to 127.0.0.1=localhost. Anything 
else is non-standard, and while I can't rule out that VirtualBox might 
have accidentally changed its behavior slightly in this area I can't 
imagine how you ever got reliable "cross-host" behavior of 127.x.x.x.

This is actually not specific to VirtualBox at all, this is generic IP 
standard definition.

Klaus

> Regards
> -Shiv
>
> On Thu, Jan 10, 2013 at 5:40 PM, Klaus Espenlaub
> <klaus.espenlaub at oracle.com <mailto:klaus.espenlaub at oracle.com>> wrote:
>
>     On 10.01.2013 07:44, manvi singh wrote:
>      > Hi - I have been using VB-3.0.14 since a long time. And my topology
>      > consists of multiple VMs communicating with each other. I have been
>      > using 127.* as the comminication interfaces (IP's) between the
>     VMs. Now
>      > i want to move to the latest VB version. But with the latest version,
>      > the communication between the VMs dont happen. I suspect the the
>     reason
>      > to be the 127 IP addresses are no more allowed to go out of the VM.
>
>     I can't follow. localnet (127.0.0.0/8 <http://127.0.0.0/8>) is
>     always local to a particular
>     operating system, and VirtualBox can't change that. It was never able to
>     extend 127.0.0.0/8 <http://127.0.0.0/8> to reach the host or any
>     other VM.
>
>     Please explain what your exact setup was, maybe it gives clues how your
>     setup was actually working, because I don't believe that the model in
>     your head and reality really matched.
>
>      > I would like to keep my IP address intact and dont want to change.
>      > Please provide the below clarifications
>      > 1. How do i get past this limitation introduced in VB. Can i get the
>      > source code and make the changes to overcome this?
>      > 2. Since which version was this support taken away, so that i can use
>      > the previous versions atleast
>
>     There has been no behavior change in VirtualBox in this area, simply
>     because VirtualBox does not have control over the meaning of
>     127.0.0.0/8 <http://127.0.0.0/8>, neither on the host or in the VM.
>     It's purely up to the OS.
>
>     Klaus
>
>      >
>      > Thanks a lot in advance
>      > Manvi
>
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