Update

In my case the problem is about our ISP's network, they have some filtering device/software that work incorrectly, then it blocks our large mail to Yahoo.

Dear all

Recently I founded an Exchange Server problem that I cannot know why it happens. I'm working on Exchange Technology since 2000 and this is the first problem that I cannot find any resolution. Please help me if you can.

My new company use a newly implement Exchange Server 2013 (No previous version in this company).

Our sending IP is not listed in any RBL, I have reverse DNS record that matched the sending IP (also matched MX record), Sending IP is on SPF record.

Send connector is using MX's DNS name in HELO message (Force HELO is enabled).

I can send mail to all major mail provider (Gmail, Outlook.com and others) except the Yahoo.

In many testing I founded most of smaller mail (0-3 MB) can send to Yahoo without any problems, but bigger mail (In the test I use 10MB attachment) can't.

I check all my firewall/content filtering gateway, no filtering settings or something like that is founded. For Exchange Server, no message size restriction is configured and no special configuration for Yahoo.

I also test my configuration with Exchange Remote Connectivity Analyzer (Outbound SMTP) and no problem founded.

I check the SMTP log and found this error

HandleError has encountered a suspicious connection reset from a remote, non-mailbox transport server (will retry in 00:10:00)

The full log is (I change the real domain and some privacy data)

2013-07-22T16:30:04.335Z,Mail Connector,08D053603E76D1D8,0,,98.136.216.26:25,*,,attempting to connect
2013-07-22T16:30:04.351Z,Mail Connector,08D053603E76D1D8,1,192.168.1.13:32418,98.136.216.26:25,+,,
2013-07-22T16:30:04.834Z,Mail Connector,08D053603E76D1D8,2,192.168.1.13:32418,98.136.216.26:25,<,220 mta1075.mail.gq1.yahoo.com ESMTP YSmtpProxy service ready,
2013-07-22T16:30:04.834Z,Mail Connector,08D053603E76D1D8,3,192.168.1.13:32418,98.136.216.26:25,>,HELO mymail.com,
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,4,192.168.1.13:32418,98.136.216.26:25,<,250 mta1075.mail.gq1.yahoo.com,
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,5,192.168.1.13:32418,98.136.216.26:25,*,,sending message with RecordId 12309376270368 and InternetMessageId <f6ca2855b4e549969e9d71d7dc7302da@srv1.mymail.com>
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,6,192.168.1.13:32418,98.136.216.26:25,>,MAIL FROM:<usr1@mymail.com>,
2013-07-22T16:30:05.521Z,Mail Connector,08D053603E76D1D8,7,192.168.1.13:32418,98.136.216.26:25,<,250 sender <usr1@mymail.com> ok,
2013-07-22T16:30:05.521Z,Mail Connector,08D053603E76D1D8,8,192.168.1.13:32418,98.136.216.26:25,>,RCPT TO:<yahoousr@yahoo.com>,
2013-07-22T16:30:05.770Z,Mail Connector,08D053603E76D1D8,9,192.168.1.13:32418,98.136.216.26:25,<,250 recipient <yahoousr@yahoo.com> ok,
2013-07-22T16:30:06.051Z,Mail Connector,08D053603E76D1D8,10,192.168.1.13:32418,98.136.216.26:25,>,DATA,
2013-07-22T16:30:06.067Z,Mail Connector,08D053603E76D1D8,11,192.168.1.13:32418,98.136.216.26:25,<,354 end data with <CR><LF>.<CR><LF>,
2013-07-22T16:30:10.793Z,Mail Connector,08D053603E76D1D8,12,192.168.1.13:32418,98.136.216.26:25,*,,"HandleError has encountered a suspicious connection reset from a remote, non-mailbox transport server (will retry in 00:10:00)."
2013-07-22T16:30:10.793Z,Mail Connector,08D053603E76D1D8,13,192.168.1.13:32418,98.136.216.26:25,-,,Remote

At present, because we cannot send mail directly to Yahoo, then we send mail to Yahoo via our ISP's relay (we add ISP's relay IP to our SPF record) and it works fine. But for me, this solution is not a good solution because our ISP's relay has some restriction and I'm not sure they will block us or not in the future if their policy changed. 

Please help me if you can.

Regards

Jun.

New 2013 implementation... Two Servers (Front End and Back End) both running Exchange 2013.

I am having trouble sending a local AD Exchange mailbox mail to external SMTP address.  I have tried several options.. I have created an "contact" as was required in previous versions.  I have created new AD accounts with external SMTP addresses, I have also attempted to use the scriptlet:

Set-Mailbox -Identity "%AD-USER%" -DeliverToMailboxAndForward $true -ForwardingSMTPAddressexternaluser@mail.com  (%AD-USER% was actual AD Username/mailbox) andexternaluser@mail.com was actual receipient SMTP address (username@gmail.com)

Local AD Mailbox receives the mail appropriately however I have enabled forwarding everyway I know how and nothing seems to work.  If I send mail straight from my account to the destination SMTP address, they get it; just not if it is sent to the local AD account then forwarded via -DeliverToMailboxAndForward command...

Please help.. I have several users that I need to have their mail CC'd to an external SMTP address.. Previous versions of Exchange required a "Contact" to be created and then the mailbox forwarded to that contact, which had a SMPT mail address...

Im not adverse to implementing via powershell if I can just get it to work... Any suggestions are greatly appreciated and needed.

We moved to another location and got a new ip from ISP and our exchange server is not able to send emails to some recipients getting .mail.protection.outlook.com error.

user@domain.com
BN1AFFO11FD036.mail.protection.outlook.com #550 5.7.1 Service unavailable; Client host [72.76.xxx.xx] blocked using Blocklist 1; To request removal from this list please forward this message todelist@messaging.microsoft.com ##

This is the error I am getting and I did email to delist@messaging.microsoft.com and I am wondering when will my IP get unblocked as this is causing a lot of communication issues. I checked my ip for blacklist but its not in any database. Hope I'll be able to find some solution soon on this.

I have Exchange 2013 CU2. Recently, one of our users received an e-mail message with sender's addressuser_a.b.@domain.com. It was impossible to reply to that address because Exchange refused to accept it:

----- The following addresses had permanent fatal errors ----- <ADDRESS> (reason: 501 5.1.3 Invalid address)

It was possible to send the message if the second dot was removed (i.e. no more ".@" combination). Of course, it could not be delivered anyways (no such mailbox).

I've conducted some experiments and found that both my mail server running Sendmail and Google mail system accept that address and deliver messages to it.

Why does Exchange behave in such a way?

I have a fresh install of 2 2013 servers  Front CAS and Back MBX role coexistent with 2007.

It was working fine until this weekend when we moved the DNS names to 2013. Meaning we moved owa/ol etc site names in DNS  and adjusted the virtual directories on both 2007 to legacy.xxx.com and mail.xx.com to the new 2013.

What now is happening is the 2 services "microsoft Exchange mailbox transport submission and microsoft exchange mailbox transport delivery services are not starting.. The only error i get is the standard "the service did not respond to the start or control request in a timely fashion."e

Its preventing any 2013 mialbox from send/recieve.  

I have checked and IPv6 is ON, the connectors are scoped ONLY to the IPv4 address. The MBX server is configured with internal/external DNS and the send connector is using external DNS.  I found that here http://social.technet.microsoft.com/Forums/exchange/en-US/26cc797d-6a40-4e18-bdb9-0e0387a12da1/the-microsoft-exchange-mailbox-transport-submission-service-terminated-unexpectedly 

Need help resolving this as its preventing moving anymailboxes to it.. All other services are working OWA proxy to 2007 etc and mail flow to and from 2007 are all working..

Thanks, Grady Vogt

Hi all,

I've got an issue with Exchange 2007 and an Exchange Online mail service (Office365). I was pointed here for additional assistance. The issue is Exchange 2007 users cannot mail Office365 users. I have verified it's not on the Office365 end as I can send and receive emails from other services such as Google Mail.

Background:

We have 3 domains, I'll name them as colors to distinguish them and for privacy reasons. Here's the list with their purpose:

• white.local.lan - internal domain
  
• red.com - Faculty Email Domain (Exchange 2007) and Website Domain
  
• blue.com - Students Email Domain (Exchange Online via Office365)

We have created a UPN suffix of blue.com in order to match them with the Office365 domain. All students are assigned this suffix. We have created records in the proxyAddresses attribute of Active Directory for the purpose of DirSync via Forefront Identity Manager. This is working well.

Every time we send an email to an address in the proxyAddresses attribute we get bounce messages as follows:

Delivery has failed to these recipients or distribution lists:
John Smith
The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

_____
Sent by Microsoft Exchange Server 2007 

Diagnostic information for administrators:

Generating server: EXCHANGE.white.local.lan
IMCEAEX-_O=NT5_ou=3865e760e8c9484fafde58fe9e1f40cf_cn=9e9257a09938de4ca69181ebb94aff38@red.com
#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##

Original message headers:
Received: from EXCHANGE.white.local.lan 
([...]) by EXCHANGE.white.local.lan 
([...]) with mapi; Thu, 22 Aug 2013 16:11:09 +1000
Content-Type: application/ms-tnef; name="winmail.dat"
Content-Transfer-Encoding: binary
From: James Elliott <James.Elliott@red.com>
To: John Smith    <IMCEAEX-_O=NT5_ou=3865e760e8c9484fafde58fe9e1f40cf_cn=9e9257a09938de4ca69181ebb94aff38@red.com>
Date: Thu, 22 Aug 2013 16:10:51 +1000
Subject: Outbound Test
Thread-Topic: Outbound Test
Thread-Index: Ac6e/lgzDPoWcQUgSC6bvsDNW0O2dg==
Message-ID: <ADBD636EDF962E4AB0F6B86D7399B14301D1274D4B@EXCHANGE.white.local.lan>
Accept-Language: en-US, en-AU
Content-Language: en-US
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator: <ADBD636EDF962E4AB0F6B86D7399B14301D1274D4B@EXCHANGE.white.local.lan>
MIME-Version: 1.0

Destination User Attributes (UPN: smithj@blue.com):

proxyAddresses:

SMTP:John.Smith@blue.com;smtp:smithj@blue.com;SIP:John.Smith@blue.com

mail:

John.Smith@blue.com

mailNickname

<not set>

We have set up the following in Exchange 2007:

[Organization Configuration] -> [Accepted Domains]

Accepted Domain: blue.com
Default: False
After MSEXCH Accepts: External Relay Domain

[Organization Configuration] -> [Send Connectors]

GENERAL
Protocol Logging Level: None
Specify the FQDN this connector will provide in response to HELO or EHLO:<blank>
Max Message Size (KB): 10240

ADDRESS SPACE
Type: SMTP
Address: blue.com
Cost: 1
Scoped Send Connector: unchecked / no

NETWORK
Select how to send mail with this connector: Use domain name system (DNS) "MX" records to route mail automatically
Enable Domain Security (Mutual Auth TLS): unchecked / no
Use the External DNS Lookup Settings on the transport server: checked / yes

SOURCE SERVER
Name:<Exchange Hostname>
Site: <Site Name>
Role: Mailbox, Client Access, Hub Transport

In Exchange 2013 both for Mailboxes and for mail enabled public folders using the EAC there does not seem to be a way to forward mail to an Exchange Contact  or group, but only to a usermailbox.  

I have seen posts in regards to how to make this work: http://social.technet.microsoft.com/Forums/exchange/en-US/381aac81-d477-4dc4-9de8-d1a527c93133/exch-2013-forwarding-mail-from-local-account-to-external-smtp-user

I posted on the tail of the question above, but realized this probably should be in its own thread.

I am looking for the comparable commands to forward mail to an exchange contact with an external smtp address for Public Folders.

Does anyone have this information?

Fred Zilz

Hi there,

I am struggling with understanding security implication of the anonymous permission on the default receive connector. I am looking for a steer in the right direction:)

I have exchange 2010 SP3 stand alone server with hub transport behind a firewall (no edge). We do have a 3rd party service (spam filter) that relays clean emails to our exchange server.

Currently i have a default setup receive connector that is configured to receive emails for any IP and a rule in the firewall to relay traffic on port 25 to the exchange server.

Recently i came to realization that all of my internal devices such as multi functional printers, UPS, NAS, etc are able to send notification emails to me without any authentication involved. That would mean, if say a virus hit any of my client computers, it would have a green light to spam everyone internally or externally without much effort!

Is this correct?

Obviously, if i uncheck anonymous permission in default receive connector, my server won't be able to receive anything at all.

Are there any best practices to secure this flaw? limit which anonymous INTERNAL devices can use my exchange as a relay? how about External anonymous clients, is it a concern?

Hello guys

Exchange 2010 SP1/ 

Here is my requirement. 

We have 3 Databases. VIP, Normal Users, accounts. I have created User Group Call "Help Desk" . They Should be able to modify the User Attributes ( such as Display Name ) only  user inside the Normal Users. 

They should not be able to do any changes for users inside VIP . 

how can we do this ?

regards 

#554 5.4.4 SMTPSEND.DNS.NonExistentDomain; nonexistent domain ##<o:p></o:p>

Original message headers:<o:p></o:p>

Received: from HPSERVER.STINDIA.COM (192.168.0.200) by HPSERVER.STINDIA.COM<o:p></o:p>

 (192.168.0.200) with Microsoft SMTP Server (TLS) id 15.0.516.32; Thu, 22 Aug<o:p></o:p>

 2013 13:22:31 +0530<o:p></o:p>

Received: from HPSERVER.STINDIA.COM (192.168.0.200) by HPSERVER.STINDIA.COM<o:p></o:p>

 (192.168.0.200) with Microsoft SMTP Server id 15.0.516.32 via Frontend<o:p></o:p>

 Transport; Thu, 22 Aug 2013 13:22:24 +0530<o:p></o:p>

Received: from 203.201.252.2 ([203.201.252.2])       by HPSERVER.STINDIA.COM<o:p></o:p>

 (HPSERVER.STINDIA.COM)        (MDaemon PRO v13.0.0)  with MultiPOP id<o:p></o:p>

 md50000007628.msg     for <>; Thu, 22 Aug 2013 13:19:27 +0530<o:p></o:p>

X-Spam-Processed: HPSERVER.STINDIA.COM, Thu, 22 Aug 2013 13:19:27 +0530     (not<o:p></o:p>

 processed: domain stindia.co.in is excluded from spam filtering)<o:p></o:p>

X-MDMultiPOP: <o:p></o:p>

X-Rcpt-To: <o:p></o:p>

X-MDRcpt-To: <o:p></o:p>

X-MDRemoteIP: 203.201.252.2<o:p></o:p>

X-Envelope-From: <o:p></o:p>

Received: from in.outbound.mailhostbox.com ([115.114.58.25]) by<o:p></o:p>

 rapidwebdns.com with MailEnable ESMTP; Thu, 22 Aug 2013 13:18:06 +0530<o:p></o:p>

Received: from kamlesh (static-mum-59.181.158.178.mtnl.net.in<o:p></o:p>

 [59.181.158.178])     (Authenticated sender:      by<o:p></o:p>

 in.outbound.mailhostbox.com (Postfix) with ESMTPA id 91D5D1680260   for<o:p></o:p>

<>; Thu, 22 Aug 2013 07:48:19 +0000 (GMT)<o:p></o:p>

Message-ID: <o:p></o:p>

Reply-To: "Steel Tubes India - Kamlesh D. Jain" <o:p></o:p>

From: "Steel Tubes India - Kamlesh D. Jain" <o:p></o:p>

To: "Steel Tubes [India] - Sales" <<o:p></o:p>

Subject: EMAL<o:p></o:p>

Date: Thu, 22 Aug 2013 13:18:53 +0530<o:p></o:p>

Organization: Steel Tubes India - Kamlesh D. Jain<o:p></o:p>

MIME-Version: 1.0<o:p></o:p>

Content-Type: multipart/mixed;<o:p></o:p>

        boundary="----=_NextPart_000_00FC_01CE9F3A.25E61BC0"<o:p></o:p>

X-Priority: 3<o:p></o:p>

X-MSMail-Priority: Normal<o:p></o:p>

Importance: Normal<o:p></o:p>

X-Mailer: Microsoft Windows Live Mail 15.4.3555.308<o:p></o:p>

Disposition-Notification-To: "Steel Tubes India - Kamlesh D. Jain"<o:p></o:p>

      <o:p></o:p>

X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3555.308<o:p></o:p>

X-CTCH-RefID: str=0001.0A0C0207.5215C244.0108,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0<o:p></o:p>

X-CTCH-VOD: Unknown<o:p></o:p>

X-CTCH-Spam: Unknown<o:p></o:p>

X-CTCH-Score: 0.000<o:p></o:p>

X-CTCH-Rules:<o:p></o:p>

X-CTCH-Flags: 0<o:p></o:p>

X-CTCH-ScoreCust: 0.000<o:p></o:p>

X-CTCH-SenderID: <o:p></o:p>

X-CTCH-SenderID-TotalMessages: 1<o:p></o:p>

X-CTCH-SenderID-TotalSpam: 0<o:p></o:p>

X-CTCH-SenderID-TotalSuspected: 0<o:p></o:p>

X-CTCH-SenderID-TotalBulk: 0<o:p></o:p>

X-CTCH-SenderID-TotalConfirmed: 0<o:p></o:p>

X-CTCH-SenderID-TotalRecipients: 0<o:p></o:p>

X-CTCH-SenderID-TotalVirus: 0<o:p></o:p>

X-CTCH-SenderID-BlueWhiteFlag: 0<o:p></o:p>

X-ME-Bayesian: 15.583860<o:p></o:p>

X-MDRedirect: 1<o:p></o:p>

X-MDRedirect_From:<o:p></o:p>

X-Return-Path:<o:p></o:p>

X-MDaemon-Deliver-To: <o:p></o:p>

Return-Path: <o:p></o:p>

Greetings everyone,

First, my apologies for posting a 2003 question in a 2013 forum, but the categories provided are 2013-only.

I have a standalone Windows 2008 R2 server with SMTP services and a custom app that generates email.  I would like to create a domain entry on the SMTP service so messages that are destined for corporate recipients get sent from the DMZ directly to the corporate Exchange 2003 server.  The Exchange server seems to be refusing connections from the standalone server even if I add its IP to the relay list; I don't get an error, the connection seems to timeout.  Does anyone know how would I go about getting this working with some security?

Thanks in advance for your help,

S_B

I think I can change it through ECP on Send/Receive Connectors, right? I know that's for Message Size Limit, not for Attachment, but I think there's not a big difference as for my case.

After changing it, what services I need to restart to make it work?

Thanks.

Lawrence Fung

We recently upgraded from an Exchange 2007 server to an Exchange 2013 server. We recreated the relays as best we could and now we have a couple of our users that are experiencing issues. They use an outside bulk email web service when they have to send updates to many of their clients (usually @ 100 - 300) and they can now only send to 5 clients at a time.

The way it works is they input their email address through the web service, our SMTP address, and authenticate through us. It then sends out the emails using our relay so it goes out as them and provides the delivery report of who was sent the email. Since the move to Exchange 2013 they are now limited to 5 at a time and show "Delivery successful" while the rest show as:

"Delivery Failure, Expected "250", Instead Reported 421 4.4.2 Message submission rate for this client has exceeded the configured limit"

I have made changes using the Get-ReceiveConnector and changed the MessageRateLimit from 5 to 50 and it still does not work. I even changed them all (unnecessary, but getting desperate) to unlimited at one point to test and it still only allows 5 at a time.

I realize this is a configuration setting somewhere, I just can't find it. Any direction on this would be appreciated.

~Rick

I am planning a migration from a Lotus Notes to Exchange 2013 environment that is site resilient. I understand that there will be a migration period and that the mail routing design will look different during that time of the migration. I have been researching the architecture of Exchange 2013 and I feel I have a pretty good understanding of most features in the CAS and DAG roles but it is really unclear how inbound/outbound external mail routing is configured. In previous versions many people used the Edge Transport server and I can still use the Exchange 2010 Edge Transport server in 2013 as one option. I am also finding information that I can setup send and recieve connectors on the Exchange 2013 CAS servers to do this task too. Below are my questions about this topic.

1. Am I right that Exchange 2013 CAS or Exchange 2010 Edge Transport are options for this service?
2. Are there other option for Inbound/Outbound External mail routing with Exchange 2013? Third party or otherwise?
3. Of all my options what are the pros/cons to using each one.
4. I have heard rumors of an Exchange 2013 Edge Transport service that is planned for future release? Are there any details on what this will feature, when it will be released, or how it will work?

In a new Exchange 2013 deployment I am trying to understand my options for Spam/AV Filtering for email.  I have read that there is a feature on the Exchange 2013 Mailbox server role that will catch spam. I also read that Microsoft offers a cloud based spam filtering/av scanner service for purchase. Exchange 2010 Edge Transport server appears to be an option yet too. I also know there are many 3rd party tools that can be utilized as well.

Are my research results for my options above correct? Are there any other options I am missing.

How good of a spam filter tool comes with the Exchange 2013 mailbox role?

I just configured my intranet exchange server alongside Server 2012.

Presently, I can successfully send mail to public web mails but on the other hand,

my web mail cant receive mail from the public. I even tried giving it a public IP; still nothing happens.

From my gmail account, error generated is this:

Technical details of permanent failure:
DNS Error: Domain name not found.

Can anyone help, please

Update

In my case the problem is about our ISP's network, they have some filtering device/software that work incorrectly, then it blocks our large mail to Yahoo.

Dear all

Recently I founded an Exchange Server problem that I cannot know why it happens. I'm working on Exchange Technology since 2000 and this is the first problem that I cannot find any resolution. Please help me if you can.

My new company use a newly implement Exchange Server 2013 (No previous version in this company).

Our sending IP is not listed in any RBL, I have reverse DNS record that matched the sending IP (also matched MX record), Sending IP is on SPF record.

Send connector is using MX's DNS name in HELO message (Force HELO is enabled).

I can send mail to all major mail provider (Gmail, Outlook.com and others) except the Yahoo.

In many testing I founded most of smaller mail (0-3 MB) can send to Yahoo without any problems, but bigger mail (In the test I use 10MB attachment) can't.

I check all my firewall/content filtering gateway, no filtering settings or something like that is founded. For Exchange Server, no message size restriction is configured and no special configuration for Yahoo.

I also test my configuration with Exchange Remote Connectivity Analyzer (Outbound SMTP) and no problem founded.

I check the SMTP log and found this error

HandleError has encountered a suspicious connection reset from a remote, non-mailbox transport server (will retry in 00:10:00)

The full log is (I change the real domain and some privacy data)

2013-07-22T16:30:04.335Z,Mail Connector,08D053603E76D1D8,0,,98.136.216.26:25,*,,attempting to connect
2013-07-22T16:30:04.351Z,Mail Connector,08D053603E76D1D8,1,192.168.1.13:32418,98.136.216.26:25,+,,
2013-07-22T16:30:04.834Z,Mail Connector,08D053603E76D1D8,2,192.168.1.13:32418,98.136.216.26:25,<,220 mta1075.mail.gq1.yahoo.com ESMTP YSmtpProxy service ready,
2013-07-22T16:30:04.834Z,Mail Connector,08D053603E76D1D8,3,192.168.1.13:32418,98.136.216.26:25,>,HELO mymail.com,
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,4,192.168.1.13:32418,98.136.216.26:25,<,250 mta1075.mail.gq1.yahoo.com,
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,5,192.168.1.13:32418,98.136.216.26:25,*,,sending message with RecordId 12309376270368 and InternetMessageId <f6ca2855b4e549969e9d71d7dc7302da@srv1.mymail.com>
2013-07-22T16:30:05.255Z,Mail Connector,08D053603E76D1D8,6,192.168.1.13:32418,98.136.216.26:25,>,MAIL FROM:<usr1@mymail.com>,
2013-07-22T16:30:05.521Z,Mail Connector,08D053603E76D1D8,7,192.168.1.13:32418,98.136.216.26:25,<,250 sender <usr1@mymail.com> ok,
2013-07-22T16:30:05.521Z,Mail Connector,08D053603E76D1D8,8,192.168.1.13:32418,98.136.216.26:25,>,RCPT TO:<yahoousr@yahoo.com>,
2013-07-22T16:30:05.770Z,Mail Connector,08D053603E76D1D8,9,192.168.1.13:32418,98.136.216.26:25,<,250 recipient <yahoousr@yahoo.com> ok,
2013-07-22T16:30:06.051Z,Mail Connector,08D053603E76D1D8,10,192.168.1.13:32418,98.136.216.26:25,>,DATA,
2013-07-22T16:30:06.067Z,Mail Connector,08D053603E76D1D8,11,192.168.1.13:32418,98.136.216.26:25,<,354 end data with <CR><LF>.<CR><LF>,
2013-07-22T16:30:10.793Z,Mail Connector,08D053603E76D1D8,12,192.168.1.13:32418,98.136.216.26:25,*,,"HandleError has encountered a suspicious connection reset from a remote, non-mailbox transport server (will retry in 00:10:00)."
2013-07-22T16:30:10.793Z,Mail Connector,08D053603E76D1D8,13,192.168.1.13:32418,98.136.216.26:25,-,,Remote

At present, because we cannot send mail directly to Yahoo, then we send mail to Yahoo via our ISP's relay (we add ISP's relay IP to our SPF record) and it works fine. But for me, this solution is not a good solution because our ISP's relay has some restriction and I'm not sure they will block us or not in the future if their policy changed. 

Please help me if you can.

Regards

Jun.