Good afternoon everyone.
This is my first post to the list and also my first step in to the world of exim, so please forgive any inaccurate statements I may make.
I have been asked to help with an issue, however I'm not sure if I have all the details correct.
In it's most basic form, Company A is having trouble emailing Company B.
Company A's mail server is managed by Company C and Company B's mail server is managed by Company D.
Company C is running Exim 4.62 and I am not sure what mail server Company D are running.
When Company A try to email Company B they receive this error.
SMTP error from remote mail server after RCPT TO:<user@???>:
host company-c.gateway [x.x.x.x]:
550-Recipient verification failed (recipient) Callout verification failed:
550 550 #5.1.0 Rejected by bounce verification.
>From reading http://www.exim.org/exim-html-3.20/doc/html/spec_45.html#SEC805 I see that exim does a callback when it receives an email, but does it do a callout before _sending_ an email ?
It seems Company D reject verification if MAIL FROM: is null. I tested it by doing the following.
telnet companyd.com 25
Trying x.x.x.x...
Connected to companyd.com (x.x.x.x).
Escape character is '^]'.
220 ***************************
HELO companya.com
250 companyd.com
MAIL FROM:<>
250 sender <> ok
RCPT TO:<user@???>
550 #5.1.0 Rejected by bounce verification.
To ensure that it was because of a null MAIL FROM: I then ran the following test.
telnet companyd.com 25
Trying x.x.x.x...
Connected to companyd.com (x.x.x.x).
Escape character is '^]'.
220 ***************************
HELO companya.com
250 companyd.com
MAIL FROM:<user@???>
250 sender <user@???> ok
RCPT TO:<user@???>
250 recipient <user@???> ok
DATA
354 go ahead
Subject:Test from me@???
Please email me@??? if this is received
.
250 ok: Message 21723617 accepted
QUIT
221 companyd.com
I received an email from Company B to my email saying they received the email appearing to be from Company A.
>From my findings, it would APPEAR that exim is doing some kind of user verification check before sending the email, is this correct?
To make this harder, I don't have any access to Company C or D's mail servers to look at configurations and I don't run Exim4 at home hence my plea to this list for some advice/guidance.
Is it possible to write an ACL to give to Company C which says
If (on outgoing email), the recipient is at either CompanyB.com or CompanyD.com then skip this remote user checking thing.
Or alternatively...
If (on outgoing email), the recipient is at either CompanyB.com or CompanyD.com then use a valid mail from: address in the remote user check.
Again I apologise for my lack of knowledge, I did try searching the archives, but couldn't see anything that would be of use to me.
If anyone has any ideas/suggestions on what to do.. it would be very much appreciated.
Thanks in advance.
Dave H.
