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MS Exchange Server Error 503 for inbound mail

Bad Sequence of Commands



3:16 pm on Apr 17, 2012 (gmt 0)

10+ Year Member

Hoping that 'somebody' can give me a clue about this...

We host a mail server internally that receives mail via an MX record from our domain / host.

We switched IP addresses last night at about 8pm, and had the MX record modified to point to the new IP address.

some mail is being returned with the error 503 - bad sequence of commands, however some emails are actually making it inside.

I'm thinking that this is a DNS issue and some packets are routing to the old IP address and the email server only receives parts of the incoming email.

I've looked around online concerning the error (503) and that seems to explain the lost information...

do I just sit and give DNS a chance to propagate? it's only been 12 hours'ish...

we can send out with no issues, and normal Internet traffic from the users works fine in the new IP address..

Anybody have any ideas? is there something I might have needed to change on the email server, or something to check?

I did do a telnet in and manually sent an email in (helo, etc)... and some users can succesfully send from their hotmail accounts into the company, however my personal domain email bounces with this error, and gmail bounces back also...

any help or suggestions will be gratefully accepted..

Thanks for your valuable time!


5:18 pm on Apr 18, 2012 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member Top Contributors Of The Month

Could you post the full error? Obfuscate the domain plz.

What might help is turning up logging on the receive connector on your Hub Transport server.

The 'Bad Sequence of Commands' sounds like a sending server not following RFC spec. Might be a java/php script passing on the content of a form or SPAM.

I'm an Exchange guy by day, webmaster at night :-)


6:12 pm on Apr 18, 2012 (gmt 0)

10+ Year Member

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

SMTP error from remote mail server after MAIL FROM:<outsideemail@otherdomnain.net>
host mx.example.com [#*$!.#*$!.#*$!.#*$!]:
503 Bad sequence of commands

------ This is a copy of the message, including all the headers. ------

Return-path: <outsideemail@otherdomnain.net>
Received: from 126.sub-166-249-130.myvzw.com ([#*$!.#*$!.#*$!.#*$!]:12934
by simon.genwebserver.com with esmtpsa (TLSv1:RC4-MD5:128)
(Exim 4.77)
(envelope-from <outsideemail@otherdomnain.net> )
id 1SKZCs-000W2e-Hk
for insideuser@example.com; Wed, 18 Apr 2012 12:02:19 -0600
Message-ID: <fe030a40-fe81-4864-8292-fae1c0d8d8f4@blur>
From: "Outside User"<outsideemail@otherdomnain.net>
To: insideuser@example.com
Date: Wed, 18 Apr 2012 13:02:33 -0500
X-Mailer: Motorola android mail 1.0
MIME-Version: 1.0
Subject: Re: test 1:01
X-Priority: 3
References: <E4626E3AB8061B4CA439E32417E9891701863E0D@name.ourmailserver.local>
In-Reply-To: <E4626E3AB8061B4CA439E32417E9891701863E0D@name.ourmailserver.local>
Content-Type: multipart/alternative; boundary="Motorola-A-Mail-f6o1C2zD3MaJjhlz"

Content-Type: text/plain; Format="Flowed"; DelSp="Yes"; charset="US-ASCII"
Content-Transfer-Encoding: 7bit


Any clues?
We've actually been down for 2 days now... the boss is getting edgy... :)

thanks so much for your time...


7:47 pm on Apr 18, 2012 (gmt 0)

10+ Year Member

ok a small addendum:

mail returned from gmail comes back with:

error 554 554 Transaction failed (state 9)


8:40 pm on Apr 18, 2012 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member Top Contributors Of The Month

Are you forwarding thru simon.genwebserver.com ? Have you opened a ticket for this with them?


8:46 pm on Apr 18, 2012 (gmt 0)

10+ Year Member

yes (sigh!) they say it's not on their end that eveything is going thru correctly... it wasn't a quick reply from them it ended up going to their 2nd tier support...

so I'm at a real loss on this...
I'm almost ready to bring in someone that knows exchange...

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