Messages in this thread |  | | Subject | Re: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19] | Date | Thu, 6 Sep 2001 15:33:24 -0400 (EDT) | From | (Wietse Venema) |
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dean gaudet: > On Thu, 6 Sep 2001, Wietse Venema wrote: > > > Andrey Savochkin: > > > > That is not practical. Surely there is an API to find out if an IP > > > > address connects to the machine itself. If every UNIX system on > > > > this planet can do it, then surely Linux can do it. > > > > > > Let me correct you: you need to recognize not addresses that result in > > > connecting to the _machine_ itself, but connecting to the same _MTA_. > > > > The SMTP RFC requires that user@[ip.address] is correctly recognized > > as a final destination. This requires that Linux provides the MTA > > with information about IP addresses that correspond with INADDR_ANY. > > > > I am susprised that it is not possible to ask such information up > > front (same with netmasks), and that an application has to actually > > query a complex oracle, again and again, for every IP address. > > how does your MTA figure out that it's behind a NAT? it doesn't matter > what unix it's running on, there's no standard way for it to know that an > address translation has occured before getting to its front-door.
The MTA does not have to know. The DNS on the inside of the NAT gateway should list "inside" machines by their "inside" address.
That eliminates a lot of other problems as well.
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