SBS 2008 Exchange Server being Blacklisted

Posted on 2010-09-22
Last Modified: 2012-05-10
Not a good day :(

I've recently installed an SBS08 server running Exchange 2007 at one of my clients. Today they have been black listed on BARRACUDA BRBL. The server is set to use our ISP's smart-host ( and yet it still has gotten blacklisted. I have confirmed in the Send Connector that the smart host is really really there.

I have attached email headers. When the user send an email. exchange pops back the attached message headers. is my company who is sending the mail which is being blocked. is the receiving domain of my blocked mails.
Diagnostic information for administrators:

Generating server: (tcp-daemon) (TCP||44643||25) ( ESMTP [aa0f8fe95058f7c9c41d87fb394acd2f]) #< (TCP||44643||25) ( ESMTP [aa0f8fe95058f7c9c41d87fb394acd2f]) #5.0.0 smtp;554 Service unavailable; Client host [] blocked using Barracuda Reputation;> #SMTP#

Original message headers:

Return-Path: <>
Received: from by
 (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) id
 <>; Wed, 22 Sep 2010 17:08:48 -0400
Received: from ( [])
 (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007))
 with ESMTP id <> for; Wed, 22 Sep 2010 17:08:48 -0400 (EDT)
Received: from DCWSBS08.domain.local ([fe80::842a:a619:3a60:40e4])
 by DCWSBS08.domain.local ([fe80::842a:a619:3a60:40e4%10]) with mapi; Wed,
 22 Sep 2010 17:08:47 -0400
Date: Wed, 22 Sep 2010 17:08:44 -0400
From: Jane Doe <>
Subject: FW: Post and Pre Logs for Deluxe
To: "" <>
Message-ID: <A947870028054547BFBCBBD69A1D430F37EDD56D@DCWSBS08.dcwcorp.local>
MIME-Version: 1.0
Content-Type: multipart/alternative;
Content-Language: en-US
Importance: high
Accept-Language: en-US
X-Priority: 1
Thread-topic: Post and Pre Logs for Deluxe
Thread-index: ActUPqy8ZLdBvQ1mQ7miHd+tQtynqQBcIsUAATq8UGAAAAgbsA==
acceptlanguage: en-US
Reporting-MTA: dns; (tcp-daemon)

Final-recipient: RFC822;
Action: failed
Status: 5.0.0
Remote-MTA: dns; (TCP||44643||25)
( ESMTP [aa0f8fe95058f7c9c41d87fb394acd2f])
X-Supplementary-Info: <
(TCP||44643||25) ( ESMTP
[aa0f8fe95058f7c9c41d87fb394acd2f]) #5.0.0 smtp;554 Service unavailable;
Client host [] blocked using Barracuda Reputation;>

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Question by:VCSLI
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Expert Comment

ID: 33740692
Your smart host ( is not blacklisted.  It looks like the culprit IP was but it is not blacklisted now so it looks like Barracuda has delisted the IP and you should be able to send that email now.

You can check your IPs here:

or use the last line in the header

Author Comment

ID: 33740700
I change the IP for the post due to privacy. The real IP is It is Blacklisted.

Barracuda has removed it but now Tiopan has added it.

Accepted Solution

cmartell earned 500 total points
ID: 33740778
Your ip may have been used by a spammer previously if you are bing blacklisted everywhere.  Or possibly your ISP allowed spamming activity and the whole range of IPs is blacklisted.

Herre are instructions to be delisted from Tiopan
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Author Comment

ID: 33740809
I have already emailed them.

The point is, how do i prevent the server from being blacklisted? I thought using a smart-host was enough since email isn't seen as being sent from the server. If i change the PTR, will that help? What shall i change it to? (mail server address)? If i have to fight daily with blacklists, thats not going to be a good thing...

I can hear angry people already. :(

There has to be a way to prevent this from happening to begin with.

Assisted Solution

cmartell earned 500 total points
ID: 33740851
blacklists go by reputation.  If you are constantly being blacklisted then someone in your organization is spamming or your ISP has a reputation for allowing spamming.  Blacklists can make mistakes but if it happens frequently then you have to do some investigating to find out why.  There is nothing yo can do to prevent being blacklisted other than ensuring that there is no spam originating from your IP.

I suppose you could add an SPF record to your DNS to be sure somebody isn't forging your domain into their spam email headers.

Author Comment

ID: 33740856
The network is entirely clean. There are no non domain joined computers on it. All client computers are running fully updated AV software. The setup is less than a week old.

Expert Comment

ID: 33742295
Well, to be save, if you have a firewall, just block port 25 outgoing. Only open it for your SBS server.

I had a client with up to date AV, but still one desktop was spamming.

Author Comment

ID: 33749580
Port 25 blocked on all but the server. I enabled logging to tell me which machine is trying to send out on the port. Hopefully this will shed some light if this is indeed the issue. Will post back in a few days.

Assisted Solution

cmartell earned 500 total points
ID: 33750617
There probably isn't anything wrong with your network if it's only a week old.  It culd be that a range of IPs is blacklisted and youre on that range.  If you continue to be blacklisted I would call your ISP.  

Author Closing Comment

ID: 33758945
Ok well  have blocked port 25 on all outbound traffic except the Exchange server. Will see how things go. Thanks everyone for the advice.

Author Comment

ID: 33760367
I have not seen anything pop up in the firewall log. It doesn't seem like any computer in the network was ever sending out on port 25. I cant say for sure if its resolved or if we'll be blacklisted again next week. Will have to see how things go. The advice offered was all very well written and well understood, but i dont know if it specifically solved my issue.

Assisted Solution

cmartell earned 500 total points
ID: 33761211
Like I said in my first posts, you "resolve " the issue by going to the RBL website and asking them to delist your IP.  There is nothing else you can do short of getting a new IP (which may not help if you are on a range of black listed IPs) or going to a different ISP.  If the previous owner of your IP was a spammer then you are probably on a bunch of black lists and you will have to request removal as you discover them.

Expert Comment

ID: 33761233
I provided you with a resolution and you awarded the points to scraane who only gave you a troubleshooting tip to see if there was a problem on your network.  If you had found a problem then you could have taken advice from scraane or someone else to fix it and awarded the points accordingly but there is no problem on your network so as it stands I have provided the only resolution.

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