On 5 May 1999 nbecker@??? wrote:
> Is there any RFC that specifies what constitutes ridiculously long?
> (Or other standard)?
>
> 1999-05-04 16:36:22 ridiculously long header received from ngw2.hns.com [139.85.177.38] (more than 8191 characters): message abandoned
Not that I know of (though the SMTP RFC makes recommendations about the
length of individual lines).
Exim has to impose *some* limit, otherwise a rogue host could send
"junk: aaaaaaaaaaaaaaaaa......." forever, tying up an SMTP channel and
eventually filling all your memory (Exim keeps headers in memory). I
chose 8192 (8191 + a zero terminator) as what I thought was a
sufficiently high number that no reasonable header would ever reach it.
It is trivial to compile Exim with a larger number if you want to.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
--
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