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Re: Comments on draft-freed-sieve-environment-04

2008-03-25 08:47:10

On Sun, 2008-03-23 at 10:50 -0700, Ned Freed wrote:
Also a good point. I have added:

  The remote-host environment item defined in this specification is usually
  determined by performing a PTR DNS lookup on the client IP address. This
  information may come from an untrusted source. For example, the test:

    if environment :matches "remote-host" "*" { ... }

  is not a good way to test whether the message came from 'outside' becaus
  anyone who can create a PTR record can create one that refers to whatever
  domain they choose.

I think a simpler way to handle this is to say that the name will
be blank if it cannot be resolved into a host name. How about:

           => Host name of remote SMTP/LMTP/Submission client, if
              applicable and available. The empty string will be returned
              if for some reason this information cannot be obtained for
              the current client.

sorry, I don't understand what this means.  is the existence of a PTR
record sufficient?  it seems so, given the above added caveat.  if so --
how is a script able to detect a forgery?

med venleg helsing,
Kjetil T.