Re: How to specify the local ip address to connect from

Probably you can strace your program but should be a call to bind

Frediano


2012/10/18 Marten Lehmann <[email protected]>:
> Hello,
>
> I'm not much into the glibc socket API, but the perl module
> http://search.cpan.org/~gbarr/IO-1.25/lib/IO/Socket/INET.pm manages to
> exactly do this: Define the local IP (and even port) a connection is
> made from.
>
> First it looks if the option LocalAddr is specified, otherwise it leaves
> the decision to the OS:
>
> $laddr = defined $laddr ? inet_aton($laddr) : INADDR_ANY;
>
> And then, before connect() is called, it binds to the interface:
>
> if($lport || ($laddr ne INADDR_ANY) || exists $arg->{Listen}) {
>      $sock->bind($lport || 0, $laddr) or
>          return _error($sock, $!, "$!");
> }
>
> If someone knows the underlying socket API of the OS, he can surely
> adapt this to create a localaddr option or similar for FreeTDS.
>
> Kind regards
> Marten Lehmann
>
> On 18.10.2012 07:36, James K. Lowden wrote:
>> On Thu, 18 Oct 2012 04:18:00 +0200
>> Marten Lehmann <[email protected]> wrote:
>>
>>> How can I set the local ip address / interface that FreeTDS connects
>>> from to the remote database host?
>>
>> There is no facility in FreeTDS to control which interface is used.  I
>> cannot offhand think of any way to control that using the standard
>> socket interface i.e. connect(2).   That sort of thing would be
>> governed by the routing tables within the machine hosting the FreeTDS
>> application.
>>
>> If I may ask, what prompts you to introduce a firewall between your
>> webserver and your database server?  Surely the database server is on
>> a network not accessible from the outside?
>>