Re: [exim] Mailformed Message-ID

Góra strony
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Autor: Richard Clayton
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Dla: palmeida
CC: exim-users
Temat: Re: [exim] Mailformed Message-ID
In message <48596.10.20.115.15.1200057529.squirrel@???>,
Paulo Almeida <palmeida@???> writes

>About the Message-ID header RFC2822 3.6.4 says that:
>
>"...a good method is to put the domain name (or a domain
>literal IP address) of the host on which the message identifier
>was created on the right hand side of the "@", and put a
>combination of the current absolute date and time along
>with some other currently unique(perhaps sequential) identifier
>available on the system (for example, a process id number) on
>the left hand side."


Some messages don't have message IDs... you might like to assume that
this is an indicator of badness, but you may in some circumstances
(notably very simple devices sending email) you will be wrong :(

>My question is if we should reject messages that the Message-ID
>is malformed


You will sometimes reject good messages if you do this. You may view
this as acceptable and everyone applauds because you block more spam, or
you may have users who will suggest that you should be sacked from your
job because the message they wanted to receive was rejected....

>and if Exim has the capability to verify the
>Message-ID header syntax.
>For example, it will be sufficient to reject a message if the
>Message-ID has no hostname after '@' ?


It's not generally a good idea ... there is a lot of software out there
which is broken or badly configured.

But by all means let a Bayesian spam filter see the headers and include
this as one of the factors that is taken into consideration.

- -- 
richard                                              Richard Clayton


They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety.         Benjamin Franklin