Messages in this thread |  | | Subject | Re: notion of a local address [was: Re: ioctl SIOCGIFNETMASK: ip alias | Date | Thu, 6 Sep 2001 13:23:16 -0400 (EDT) | From | (Wietse Venema) |
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Alan Cox: > How for example do you propose to answer the question for the case > Q: "is this local" A: "it depends on the sender" > With netfilter and transparent proxying active this is entirely possible
Please explain the relevance for a real-world, SMTP based, MTA.
If an MTA receives a delivery request for user@[ip.address] then the MTA has to decide if it is the final destination. This is required by the SMTP RFC.
In order to enable SMTP RFC compliance, Linux has to provide the MTA with the necessary information. Requiring the sysadmin to enumerate all IP addresses in a file, as suggested by some other poster, is impractical.
If an MTA receives a mail relaying request for user@domain.name then it would be very useful if Linux could provide the MTA with the necessary information to distinguish between local subnetworks and the rest of the world. Requiring the local sysadmin to enumerate all local subnetwork blocks by hand is not practical.
I will ignore denigrating comments about competing IP stacks.
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