Description:
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It would nbe nice to have a new security feature in PHP.

Actually, a web server receives connections from a specific IP/port, but any PHP script can use any available address on outgoing connections.
This can be a security problem.

It should be possible to 'force' PHP to open connections only with a spcific IP or with the listening IP.This helps to prevent such problems:

 * if you have internal interfaces in the same machine where you have
   public IPs, a web PHP application could try to use the internal
   address of the interface, exploring internal network (actually we avoid that
   thanks to FreeBSD jails).
 * if apache listens on a specific  IP for a single domain, and listens
   on other IPs for others domains, it would be safe if each domain can
   use as source IP only the listening IP associated.