Blocked Email

I am using Exchange 2003 Standard and lately, I have been having problems with email being blocked or not going through to the recipient.  I get the following messages:

The following recipient(s) could not be reached:

      'username@gtlaw.com' on 6/30/2005 4:54 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;550 Denied by policy.>

The following recipient(s) could not be reached:

      'username@aol.com' on 6/30/2005 4:54 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;554-:  (RLY:CH)  http://postmaster.info.aol.com/errors/554rlych.html>

The following recipient(s) could not be reached:

      'username@law-morris.com' on 6/30/2005 12:00 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;550 <smorris@law-morris.com>, Recipient unknown>


The AOL issues seems to be that I am blocked by them due to complaints about spam.  

I would like to know what the problem is and how to fix it.  If I am being black listed, how do I get that resolved and whom do I contact to do so.  Thanks!

MC
markcondiffAsked:
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.

gpriceeeCommented:
Hi.  This isssue has to do with your reverse DNS lookup.  AOL is a pain, in my opinion; however, you can use their tools to help you resolve the issue and check the validity of your reverse lookup:
http://postmaster.aol.com/tools/rdns.html

You also can use their troubleshooting to send email to you to let you know when you're okay to send.
markcondiffAuthor Commented:
That gives me somewhere to go for help with the AOL account.  Thanks.  What about the other domains I am not getting through to?
gpriceeeCommented:
More than likely, the same issue.
Because AOL is such a pain, once AOL users can receive your email, others should be able to.
Your Guide to Achieving IT Business Success

The IT Service Excellence Tool Kit has best practices to keep your clients happy and business booming. Inside, you’ll find everything you need to increase client satisfaction and retention, become more competitive, and increase your overall success.

SembeeCommented:
Are you on a DSL or cable modem connection?

As far as many ISPs are concerned, anyone on DSL or cable should not be running their own mail server. In their eyes you should be pushing all your email through your ISPs mail server.
You will probably end up using an SMTP Connector to route email through your ISP. Whether you use this facility for all email or just domains that cause problems is up to you.

http://www.amset.info/exchange/smtp-connector.asp

Simon.
Exchange MVP.
markcondiffAuthor Commented:
I am using a T1
markcondiffAuthor Commented:
It is a business with 60 users.  All users are blocked from AOL.
SembeeCommented:
I have a client on a leased line here in the UK and they cannot send to AOL.
With AOL you have to make sure that everything is correct - reverse DNS, the name the machine announces itself as, and lots of other things.

However I have actually given up trying to conform to AOLs ideal world of email server setup, for some clients I just cannot do it exactly how AOL want. Instead I now put an SMTP Connector in for AOL on all installations that I do. It saves so much time and hassle for both me and the client.

Simon.
markcondiffAuthor Commented:
I agree with your comments about AOL.  

Any suggestions on the other 2 error messages in my original post?  I just want to be sure I am not on some blacklist.
BNettles73Commented:

gpriceee has it correct ... AOL will block your email if you do not have a PTR record setup for your MX. Basically it needs to be able to perform reverse DNS. You can do an NSLookup on your MX IP Address to verify this is setup correctly. Make sure you are using a public DNS server, or even better one of the AOL DNS servers to perform your query.

You don't have a PTR record properly, your SMTP connector or virtual server is setup improperly or you are listed on an RBL. Go to http://www.dnsstuff.com and run a Spam database lookup.
      'username@aol.com' on 6/30/2005 4:54 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;554-:  (RLY:CH)  http://postmaster.info.aol.com/errors/554rlych.html>

This looks like it was going to a mail server that did not recognize the recipient SMTP address. Check the email address again.
      'username@law-morris.com' on 6/30/2005 12:00 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;550 <smorris@law-morris.com>, Recipient unknown>

This looks like another reverse DNS issue or your domain is listed on an RBL. Go to http://www.dnsstuff.com and run a Spam database lookup.
      'username@gtlaw.com' on 6/30/2005 4:54 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;550 Denied by policy.>

If you are blacklisted, you will need to contact the administrators of the RBL. Once you run the check, you should be able to click a link to go to their website. Before contacting them, make sure your internet mail server is not an open relay.

Prevent Exchange 2003 from Relaying (Close Open Relay)
http://www.petri.co.il/preventing_exchange_2000_2003_from_relaying.htm

Brian
BNettles73Commented:


FYI ... your smorris@law-morris.com looks like a misconfiguration issue. See below:

Getting MX record for law-morris.com (from local DNS server, may be cached)... Got it!

Host Preference             IP(s)                 [Country]
mail.law-morris.com. 10 72.17.149.98        [US]
stats.socoweb.com.   20 208.179.234.190   [US]
 --------------------------------------------------------------------------------


Step 1:  Try connecting to the following mailserver:
         mail.law-morris.com. - 72.17.149.98

Step 2:  If unsuccessful in step 1, try connecting to the following mailserver:
         stats.socoweb.com. - 208.179.234.190

Step 3:  If still unsuccessful, queue the E-mail for later delivery.
--------------------------------------------------------------------------------
Trying to connect to all mailservers:

   mail.law-morris.com. - 72.17.149.98  [Successful connect: Got a good response [250 Accepted]]
   stats.socoweb.com. - 208.179.234.190  [Could not connect: Got an unknown RCPT TO response: 550 , Recipient unknown
BNettles73Commented:

The secondary MX record doesn't have the user mailbox or know where to go. If you experience connectivity issues or latency and email tries to route to that server, the email will fail.

Hope that makes sense.
markcondiffAuthor Commented:
Thanks for your help.  I will do some research and see what I come up with.

As for the RBL, My IP was listed on one:

BLARSBL  LISTED (127.1.0.1)    171457 seconds  0 ms

When I went to my Relay exceptions in Exchange, I had an exception that was 127.0.0.1  -  Which is close to the IP listed above on the RBL.  Could that be a problem?

How do I get off that list?
BNettles73Commented:


BLARSBL is not really a standard RBL, just a guy who setup his own RBL that very few people really use. I doubt that is the source of your issue.  I would wager the issues you are experiencing are RDNS issues.

You should make sure you get a PTR record added for your email server. Wherever you are hosting your DNS, you should have them create a PTR record.

Example:
yourdomain.com          MX     IN     21600   mail.yourdomain.com. [Preference = 10]
mail.yourdomain.com   MX     IN     21600   4.2.2.1
4.2.2.1                        PTR   IN     21600   mail.yourdomain.com

You should make sure that mail.yourdomain.com also resolves properly to 4.2.2.1 (keep in mind 4.2.2.1 is just an example).

If you do an NSLookup afterwards, you should see something like the following:

C:\Program Files\Support Tools>nslookup 4.2.2.1
Server:  dns1.dnsserver.com
Address:  4.1.1.1

Name:    email.yourdomain.com
Address:  4.2.2.1
Aliases:   1.2.2.4.in-addr.arpa
BNettles73Commented:

I forgot to ask, did you understand what I was saying above, in regards to the NDR below?

This looks like it was going to a mail server that did not recognize the recipient SMTP address. Check the email address again.
      'username@law-morris.com' on 6/30/2005 12:00 PM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <mail.domain.com #5.5.0 smtp;550 <smorris@law-morris.com>, Recipient unknown>

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
markcondiffAuthor Commented:
Yes, I understood.  This has been very helpful.  Thanks!
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.