Exim bug, you can send email from "one" domain to the "same" domain without Auth.

[mohamed_gaber]

Hi,

If you try to telnet to any Exim mail server :
telnet domain.com 25

Then you try to send email from "one" domain to the "same" domain on that "same" server, it will be routed successfully without Auth.

I know that is not a serious problem, or considered an open relay, but still it can be inconvenient for some server admins.

An Example illustrating that :
C:> telnet domain.com 25
220-server1.domain.com ESMTP Exim 4.43 #1 Mon, 11 Oct 2004 10:54:12 +0300
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
rset
250 Reset OK
helo sosos.com
250 server1.domain.com Hello sosos.com [62.139.139.42]
mail from:<test@domain.com>
250 OK
rcpt to:<anything@domain.com>
250 Accepted
data
354 Enter message, ending with "." on a line by itself
from: test@domain.com
to: anything@domain.com
subject: testttttttttttttt

the body message
.
250 OK id=1CGv1G-0000yP-S8

[chirpy]

That's how SMTP works and always has done, it's certainly not a bug in Exim. If you accept email to be delivered to a domain on your server, then you never require authentication when relaying to your server, no matter where it is from. You only require authentication when relaying through your server.