On Thu, 11 Dec 1997, Alan Thew wrote:
> I have
>
> sender_reject_recipients = partial-dbm;/disk2/exim/tables/blocked-senders
>
> but have found with a few addresses where there are mixed case local
> parts, exim doesn't see a match,
>
> e.g. Best-Biz@???
I wish, oh how I wish, that way back in the early 1980's when the email
standards were written, they had plumped for case independence in email
addresses. Here's what RFC 821 says:
Commands and replies are not case sensitive. That is, a command or
reply word may be upper case, lower case, or any mixture of upper and
lower case. Note that this is not true of mailbox user names. For
some hosts the user name is case sensitive, and SMTP implementations
must take case to preserve the case of user names as they appear in
mailbox arguments. Host names are not case sensitive.
Unix login names are case sensitive, but on the whole people expect
local parts in email addresses on Unix to be case insensitive. That is
why Exim by default lowercases incoming local parts *for its local
domains*, so that mail to JDoe and jdoe are treated the same, though
there is an option to change this. However, it leaves the local parts
for remote addresses alone, because of RFC 821.
Also, when it is doing a match on a remote sender, as in
sender_reject_recipients, it doesn't modify the case of the incoming
sender. At least I don't think so. The whole case-handling aspect is so
messy that it is easy to get it wrong.
--
Philip Hazel University Computing Service,
ph10@??? New Museums Site, Cambridge CB2 3QG,
P.Hazel@??? England. Phone: +44 1223 334714
--
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