9323 Hamilton
Mentor, Ohio 44060 - USA
Tel:+1-440-357-1400
Fax:+1-440-357-1416
|
9323 Hamilton Mentor, Ohio 44060 - USA Tel:+1-440-357-1400 Fax:+1-440-357-1416 |
If your email is rejected by Scientific Solutions email servers and you don't know why, then please read this web page. If you don't understand the contents of this page then contact your network system administrator and refer them to this page.
Our Scientific Solutions' email servers are configured to perform strict checks prior to receiving email messages. The primary reason for this is to reduce the amount of junk email ("spam") that we receive.
At present most mail servers on the Internet are not configured so strictly, so you may find that your email is delivered to other destinations but not to Scientific Solutions destinations.
Your mail-server is identifying itself as "some name" but when the Scientific Solutions mail-server checks the name associated with your mail-server's IP address it finds "another name".
This is because your mail server is configured incorrectly. It should be fixed.
Spammers will often misconfigure their mail-server to make it difficult to trace them. Our mail-servers require that all inbound email come from mail-servers that are configured to identify themselves properly.
As an example, take a look at three lines from our mail.log
Feb 26 19:39:33 raccoon postfix/smtpd[6985]: connect from
h-66-166-212-194.LSANCA54.covad.net[66.166.212.194]
Feb 26 19:39:34 raccoon postfix/smtpd[6985]: NOQUEUE: reject: EHLO from
h-66-166-212-194.LSANCA54.covad.net[66.166.212.194]: 450 <chef
.orbitsystems.com>: Helo command rejected: Host not
found; proto=SMTP helo=<chef.orbitsystems.com>
Feb 26 19:39:36 raccoon postfix/smtpd[6985]: disconnect from
h-66-166-212-194.LSANCA54.covad.net[66.166.212.194]
Examine these log file entries:
A "soft rejection" is used because the mismatch might be due to the fact that the other mail-server's name changed, but the DNS entry has not yet been updated, or perhaps old information is being supplied from a cache. The soft rejection allows retries to occur until DNS cache is renewed or other temporary name conflicts are resolved. So initially the sender will receive notification that the mail was not sent, but an attempt to deliver will continue for some time. However, if the mail servers "HELO name" does not match the reverse DNS query, then eventually the retries will expire and a hard rejection will result at which time the sender will get an undeliverable message.
The "HELO name" is set by the person who configured the mail-server-software. The "DNS name" is set by the Internet Provider or network systems administrator. Often it is the same person, but sometimes not.
A person who wants to send junk email (a "spammer") might get a DSL line and then setup a computer with mail-server-software. His Internet Provider might not allow the sending of "spam messages", so to confuse the end-user the spammer will configure his mail-server-software to identify itself as something other than the DNS name. When an end-user receives such junk mail and tries to complain, they complain to the "wrong party" and the spammer is free to keep sending junk email for awhile longer.
Not every server that is misconfigured is a "spam server". There are many legitimate email servers that are misconfigured. But it is difficult to differentiate between "spammers who misconfigure their mail-servers" and "legitimate mail-servers that are misconfigured because of oversight". Scientific Solutions mail-servers will not accept email from misconfigured mail servers.
Set your mail-server-software to identify itself with the same name that a "reverse DNS lookup" will provide.
Scientific Solutions mail-servers will not accept email from misconfigured mail servers, so your email will continue to be rejected.
You might raise the issue with somebody that it is embarrasing for your organization to have misconfigured mail servers. It is rather like passing out business cards on which your company name is misspelled.
As a workaround you can print and send your message by US Postal Service, or send by fax.
Here are some more log entries to help specific companies that have misconfigured mail-servers.
Consumers Power:
Connection from IP 65.221.183.37
"HELO name" is dmzhpu02.cpco.com
DNS Query for IP 65.221.183.37 returns "DNS Name"
mailout.cmsenergy.com
"dmzhpu02.cpco.com" does not match "cmsenergy.com" and so the mail is
rejected
Feb 26 21:34:00 raccoon postfix/smtpd[7148]: connect from mailout.cmsenergy.com[65.221.183.37]
Feb 26 21:34:03 raccoon postfix/smtpd[7148]: NOQUEUE: reject: EHLO from
mailout.cmsenergy.com[65.221.183.37]: 450
<dmzhpu02.cpco.com>:Helo
command rejected: Host not found; proto=SMTP
helo=<dmzhpu02.cpco.com>
Feb 26 21:34:04 raccoon postfix/smtpd[7148]: disconnect from
mailout.cmsenergy.com[65.221.183.37]
Tyco Healthcare:
Connection from IP 146.214.100.42
"HELO name" is nasmtp02.thcg.net
DNS Query for IP 146.214.100.42 returns "DNS Name"
mail02.tycohealthcare.com
"nasmtp02.thcg.net" does not match "mail02.tycohealthcare.com" and so
the mail is rejected
Feb 12 02:45:55 ei-tiger postfix/smtpd[12174]: connect from mail02.tycohealthcare.com[146.214.100.42]
Feb 12 02:45:59 ei-tiger postfix/smtpd[12174]: 72CDFB6EC9: client=mail02.tycohealthcare.com[146.214.100.42]
Feb 12 02:45:59 ei-tiger postfix/smtpd[12174]: 72CDFB6EC9: reject: RCPT
from mail02.tycohealthcare.com[146.214.100.42]: 450
<nasmtp02.thcg.net>: Helo command rejected: Host not found;
proto=ESMTP helo=<nasmtp02.thcg.net>
Feb 12 02:46:00 ei-tiger postfix/smtpd[12174]: disconnect from mail02.tycohealthcare.com[146.214.100.42]
Specifications subject to change without notice.
Scientific Solutions liability, trademarks, and export notices apply.
Copyright © 1974-2004 Scientific Solutions - All rights reserved.