Hi Ansar,

Read this: How to troubleshoot mail relay issues in Exchange Server 2003 and in Exchange 2000 Server

http://support.microsoft.com/kb/895853

A/

Emails being routed to Junk mail folder is not caused by your IP being on a blacklist.  Having your IP on a blacklist means that emails originating from your domain wilol be refused by recipients servers.  This is a totally seperate issue from mails being classified as Spam after it has been received.  To end up in the junk email folder your email is probably getting an SCL rating from Exchange Intelligent Mesage Filter.  The easiest way to avoid this is to ask people you regularly send to to add you to their white list so that your emails are not spam filtered.  This sounds to me as though the recipients have tightened up their Spam Filters rather any thing you have done.

Hi,

As Per wiscom link when i went through one of the links specified below the ip reputation is shown as risky what does it mean and how should i remove this.
 
http://www.trustedsource.org/query/91.73.173.174

Please suggest

Thanks in advance.
--Ansar

Are you sure that the messages are coming from your exchange server?
It is common for spammers to forge internal addresses and these look like they come from valid internal people, but are in fact the messages are spam / junk.
To check against blacklists - please visit http://www.mxtoolbox.com/blacklists.aspx
If the messages are not from internal sources, you need to make sure you have Exchange 2003 SP2 installed, then turn on tarpitting, Sender filtering and filter recipiets not listed in your directory.
Tarpitting - http://www.mxtoolbox.com/blacklists.aspx
Sender Filtering / filter recipients not listed - http://www.msexchange.org/tutorials/Sender-Recipient-Filtering.html

If you think your IP is incorrectly classified you will need to contact trustedsource as below.

Who can I contact if I think the reputation assigned to an IP should be changed?
If an IP is classified as 'Inoffensive' or 'Neutral' but sends out spam or if a legitimate IP is classified as 'Suspicious' or 'Spam,' please contact http://www.trustedsource.org/en/about/mailform?recipent=trustedsource.

Alan,

I have checked http://www.mxtoolbox.com/blacklists.aspx for blacklist and found its ok (not on blacklisted IP) as well the problem is that emails sent from users in my office is rejected by the recipient mail server considering as spam. all it was started 3-4 days back when email sent to one domain is failed and returned back with error
    "host 10.100.242.120[10.100.242.120] said: 554 Transaction
    Failed Spam Message not queued. (in reply to end of DATA command)"

Now there are few more domains which rejects our mail considering as spam.

Till 3-4 days all was correct and i did no changes on the server and even there are no windows updates during this issue.

--Ansar

I have seen posts where this error is caused by the recipients email server using greylisting.  Exchange doesn't handle greylisting well and you can get strange errors.  I would ask the problem domains if they are using greylisting and if they are ask them to whitelist your server.

Check your reputation on http://www.senderbase.org/senderbase_queries/rep_lookup to see if you are flagged as anything other than neutral.
I tried telnetting to the IP address on port 25 to see what type of server it was but it failed!
As DCMBS has said - you may be greylisted.
 

Hi Ansar,

You system is NOT an open relay

Testing 91.73.173.174 on port 25... successful! - the SMTP server is NOT an open relay.
on http://www.spamhelp.org/shopenrelay/shopenrelaytest.php

Try the "Domain Health Check!" on http://www.securecomputing.com/dhc/

Maybe the give som advice!

A/

First of all thanks alot for everyone's response to this post, got some good knowledge on greylisting from DCMBS post. I did try IP reputation check "SenderBase reputation score         Good " it is Good and also Domain health check "http://www.securecomputing.com/dhc/dhcsfw.cfm?domain=qanawat-me.com&pid=" which is also neutral

Even i have added spf record for our domain too "v=spf1 mx -all" but still the issue persists.

--Ansar

If it is a greylisting issue then your only recourse is to ask the recipients email admin to whitelist you.  I am finding this more and more that I have to get my server whitelisted by remote servers so that I can send them email.  SPF records do not really help with SPAM as a SPF record will only say that the server is either authorised or not.  It is mainly a defence against email address spoofing.  

DCMBS:

I dont have any event log wherein alert states as greylisting and retrying again. As per the bounced email recipient recieved this msg in spam message "The  554 Transaction  Failed Spam Message not queued. (in reply to end of DATA command)".

I added SPF record by looking at some earlier posts for the spam issue not specific to greylisting.

--Ansar

You won't usually see anything in your logs about greylisting.  As I said earlier there is no standard error message for greylisting.  You can only contact the admin of the remote server and ask him if they use greylisting.  Also you get to know over time what responses indicate greylisting.  As I said I am finding more and more I have to work in coperation with remote email admins to get my email through.  We operate our own ISP facility and have an excellent reputation with our servers approved by all the main ISPs such as AOL, Hotmail, Yahoo etc but we still get problems such as these every now and again.

Thanks for the suggestions

I have SMTP logging enabled so earlier i had seen for one domain greylisting log in my event log.

Please let me know any of the smarthost providers list who will allow IP based relay/routing so that i can approach them.

--Ansar

Your ISP will normally provide a smarthost for you to use as part of your ISP services.

Dear All,

Thanks for all the people who replied to this post.  Till now i dont know why my ip address is blocked even though it is not listed anywhere and all records are perfect. I got the solution by forwarding emails through smart host of domain hosting as i had tried earlier for smarthost relay with the ISP for which they said there is no such facility available this is due to my hosting domain is different from ISP.

Thanks again for good knowledge sharing.

--Ansar