cannot find your hostname [xxx.xxx.xxx.xxx]

Hi
I have some issues sending email to some domains...

sending to some domains I receive an "Undeliverable" email from the excahnge server with error: mail.faillingdomain.com #550 Client host rejected: no reverse DNS set. ##

to other domains the email get stuck in the Queue with Last Error desc: "Client host rejected: cannot find your hostname, [xxx.xxx.xxx.xxx]<-- outbound public ip

I called my ISP to set the PTR record to, mail.mydomain.com on outbound public ip address (.18)

my current setup is...
MX record points to a SPAM filtering supplier, then supplier send filtered emails to inbound public ip (.19) to my exchange server ...
outbound emails are going thru (.18)

header email when I send to anothe domain...

Delivered-To: lcastillo@externaldomain.com
Received: by 10.229.236.130 with SMTP id kk2cs203037qcb;
        Tue, 30 Mar 2010 15:30:13 -0700 (PDT)
Received: by 10.114.189.13 with SMTP id m13mr5942858waf.130.1269988213337;
        Tue, 30 Mar 2010 15:30:13 -0700 (PDT)
Return-Path: <lcastillo@mydomain.com>
Received: from mail.mydomain.com ([xxx.xxx.xxx.18])<-- external IP
        by mx.google.com with ESMTP id 33si13518244pzk.73.2010.03.30.15.30.12;
        Tue, 30 Mar 2010 15:30:12 -0700 (PDT)
Received-SPF: neutral (google.com: xxx.xxx.xxx.18 is neither permitted nor denied by best guess record for domain of lcastillo@mydomain.com) client-ip=xxx.xxx.xxx.18;
Authentication-Results: mx.google.com; spf=neutral (google.com: xxx.xxx.xxx.18 is neither permitted nor denied by best guess record for domain of lcastillo@mydomain.com) smtp.mail=lcastillo@mydomain.com
Received: from myexchange.mydomain.mx.mty ([xx.xx.xx.117]) <-- internal ip by
 myexchange.mydomain.mx.mty ([xx.xx.xx.117]) with mapi; Tue, 30 Mar 2010 16:30:40
 -0600
From: "Luis LC. Castillo" <lcastillo@mydomain.com>
To: "lcastillo@externaldomain.com" <lcastillo@externaldomain.com>
Date: Tue, 30 Mar 2010 16:30:38 -0600
Subject: test
Thread-Topic: test
Thread-Index: AQHK0FifB2qAPqJHP0yRfmVj4UPlew==
Message-ID: <4531BABF0478BA4482D1EE73B3F2F14889CB6E8182@mtyexc01.guentner.mx.mty>
Accept-Language: es-ES, en-US
Content-Language: es-MX
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
acceptlanguage: es-ES, en-US
Content-Type: multipart/alternative;
      boundary="_000_4531BABF0478BA4482D1EE73B3F2F14889CB6E8182mtyexc01guent_"
MIME-Version: 1.0

--_000_4531BABF0478BA4482D1EE73B3F2F14889CB6E8182mtyexc01guent_
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable



--_000_4531BABF0478BA4482D1EE73B3F2F14889CB6E8182mtyexc01guent_
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

<html dir=3D"ltr"><head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Diso-8859-=
1">
<style title=3D"owaParaStyle"><!--P {
      MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
--></style>
</head>
<body ocsi=3D"x">
<div dir=3D"ltr"><font color=3D"#000000" size=3D"2" face=3D"Tahoma"></font>=
&nbsp;</div>
</body>
</html>

--_000_4531BABF0478BA4482D1EE73B3F2F14889CB6E8182mtyexc01guent_--






lcastillo83Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

linrafCommented:
Use mxtoolbox.com to make sure that your request was done.
Make sure that you have an A record for mail.mydomain.com that points back to xxx.xxx.xxx.18 (external ip), some mail servers/ spam filters want that.
0
lcastillo83Author Commented:
in mxtoolbox.com is displayed correctly...

PTR xxx.xxx.xxx.18 mail.mydomain.com  TTL= 48 hrs

my A record for mail.mydomain.com points to .19 as it is the OWA url.

Thanks
0
Alan HardistyCo-OwnerCommented:
Please have a read of my article that discusses the problem of not being able to send mail to one or more domains:
http://www.experts-exchange.com/articles/Software/Server_Software/Email_Servers/Problems-sending-mail-to-one-or-more-external-domains.html 
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
linrafCommented:
Ptr info must match a record info. Use a different ptr name specifically for .18 and create an A record for that hostname to point to .19.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Exchange

From novice to tech pro — start learning today.