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Subject: Helo command rejected: Host not found
From: Uri Shohet (ushohetams-sys.com)
Date: Wed May 03 2000 - 05:44:43 CDT

Hi,

I'm new to this list and relatively new to Postfix, so please be gentle ;-)

I've installed and configured Postfix on an RH Linux 6.1 machine
using postfix-19991231_pl06-1 RPMs. Everything appears to be fine except this
problem: There are few hosts from which Postfix refuses to receive mail.

The log says:

May 3 10:37:03 mail postfix/smtpd[12084]: connect from
h2.hum.huji.ac.il[132.64.177.4] May 3 10:37:04 mail postfix/smtpd[12084]:
212619F73: client=h2.hum.huji.ac.il[132.64.177.4] May 3 10:37:15 mail
postfix/smtpd[12084]: reject: RCPT from h2.hum.huji.ac.il[132.64.177.4]: 450
<hum-nt4.h2.hum.huji.ac.il>: Helo command rejected: Host not found;
from=<usernameh2.hum.huji.ac.il> to=<usernameams-sys.com> May 3 10:37:20 mail
postfix/smtpd[12084]: disconnect from h2.hum.huji.ac.il[132.64.177.4]

or:

May 3 10:28:17 mail postfix/smtpd[11982]: connect from unknown[213.8.25.62]
May 3 10:28:20 mail postfix/smtpd[11982]: CFA9E9F73: client=unknown[213.8.25.62]
May 3 10:28:23 mail postfix/smtpd[11982]: reject: RCPT from unknown[213.8.25.62]:
450 <leedannt1.leedan.co.il>: Helo command rejected: Host not found;
from=<usernameleedan.co.il> to=<usernameams-sys.com>
May 3 10:28:29 mail postfix/smtpd[11982]: disconnect from unknown[213.8.25.62]

As recommended I've set the smtpd_client_restrictions like this:
smtpd_client_restrictions =
                    permit_mynetworks,
                    check_client_access hash:/etc/postfix/access,
                    reject_maps_rbl,
                    reject_unknown_hostname

I understand that reject_unknown_hostname causes this situation.
My question is what should I ask the sysadmin of that domain to fix in their
configuration, or what should I change in my configuration so that their emails
will get to our users? (especially to my boss)

Any help appreciated,

Uri Shohet 

-- 
Uri Shohet
A.M.S. Advanced Maintenance Systems Ltd.
E-Mail: ushohetams-sys.com
Tel.:   +972-2-5822477 Ext.884