Exchange 2003, DNS, MX Records and Internet Mail SMTP Connector help

Thanks for the heads-up Neilsr-I will have to search for a feature that limits amount of emails sent in a certain period---if it exists with Exchange?
We only signed a one-year contract.  We'll see how it handles it, I looked through to see amount of spam we were receiving -- incl. spam, I am hopeful it will not impact us greatly(bandwidth wise). But like you stated---don't want to deal with any type of mail-bomb coming through. There are approx. 5 email boxes that receive a significant amount of spam, users are very conservative about giving out their addys.

Your internal DNS has nothing to do with the internet for email delivery. You will need to look at an external service to see your MX record setup.

DNS record changes take up to 48 hours to propagate, so both systems need to be in a position to receive email as soon as you make any changes.

The only thing you need to be concerned about is a PTR record for outbound email delivery. Your ISP will have to set that up for you. That can be done in advance - it may already be setup.

You will need to look at your public DNS records to see what the txt records are for. They are probably SPF records.

Simon.

unfortunately, users not giving out their email addresses will not stop the tens of thousands of emails that are generated to SomeUnknownName@yourdomain.com or JoeBlogsMom@yourdomain.com etc

These will ALL have to be delivered via your ISP connection to the internal device that does your filtering before they are ditched as spam/unwanted emails. Once you lose the outside filtering you can expect to see a vast increase of inbound emails that are destined for noboday at all. It is one of the biggest selling points for hosted mail filtering. Not what you wanted to hear I know....

Whois is information on who owns a domain name.
For email, you need to have an MX record on the Internet for all domains hosted by your exchange server.
run nslookup -q=mx mydomain.com on your internal domain. If it points to your exchange server, you are good.
go to kloth.net and search for your domain on the Internet. If it goes to your email provider, you need to get the company that owns your web site to change it to the SMTP address exposed to the Internet by your firewall. There is nothing to do but switch before you cancel your other account because it will take a while for the switch to replicate throughout the Internet.
You can switch the SMTP connector to DNS and outbound mail will be delivered directly to the Internet hosts. Alternately, you can point the connector to your device for outbound scanning.

Mestha: PTR record--we have had the same ISP for awhile--wouldn't that already be set up or no? Also, would it be my ISP or the one that provides DNS to me? (diff. companies in my case--the whois showed it was our co. hosting our website--if that is wrong, how do I find out who is hosting our DNS?)  As for the public DNS records--how do I view those? The TXT records are in my internal DNS which state:
v=spf1 a include:firewallco.com; include:smarthost.com ~all
v=spf1 mx include:onlinebanking.com ?all

Neilsr-no, didn't wanna hear it--but good to know!

Jon_Harvey:ran the mxlookup command--comes back to my exchange server-should I run that from the outside?  When I go to kloth.net--enter my domain it states it cannot locate me. In reference to connector-I am now assuming this is how the new firewall co will walk me through setup...to have that conn. point to the new device?

Thanks for all your responses.

If you have been routing email via a smart host, then the PTR record may not have been setup. It isn't done automatically, only on request. You will need to check.

Emails for non-existent users are easily dealt with by using recipient filtering. The only time it becomes a problem is when that isn't enabled. At home I am actually using emails for non-existent users as part of an antispam solution!

Simon.

Mestha: How do I determine if my PTR record has been set...and how do I know for certain who hosts my DNS?

Mesta,
"Emails for non-existent users are easily dealt with by using recipient filtering. The only time it becomes a problem is when that isn't enabled."
This is not entirely true. The spam emails STill have been delivered to site to be dealt with in this way therefor consuming bandwidth. They can not be dealt with until delivered to site was my point.  

Jon_Harvey:ran the mxlookup command--comes back to my exchange server-should I run that from the outside?  When I go to kloth.net--enter my domain it states it cannot locate me. In reference to connector-I am now assuming this is how the new firewall co will walk me through setup...to have that conn. point to the new device?

It depends on the appliance you are using. I have an appliance and I noticed that the message size limits applied to both inbound and outbound messages. We didn't want to have the same limits for outbound as inbound, so we couldn't use the appliance for outbound email delivery.

Also,  I am sure most appliances use a Reputation service of some sort. When a SMTP server of ill repute attempts to connect to your appliance, the connection is severed based on their reputation as a spammer. It cuts down on a lot of traffic as the email is never delivered. Our appliance blocks 80% of the connection attempts!

Mestha: I went to kloth.net-entered my info-see who my mx records are(current email filtering co) and nameservers(same co. that hosts our firewall). For external IP, am I supposed to enter my whatismyip ip? that doesn't come back with anything.
Back to the nameserver--I should now contact that company and ask them to add them as my mx record too? I am a little confused.

"This is not entirely true. The spam emails Still have been delivered to site to be dealt with in this way therefor consuming bandwidth. They can not be dealt with until delivered to site was my point.  "

Recipient filtering blocks the message at the point of delivery. Therefore the most traffic that goes over is measured in bytes. It is three lines of text to reject the message. Not the entire message. The message is not delivered.

On the original question, if you have entered your IP address it should come back with something, even if it is just
123.123.123.123.in-addr.arpa
Do ensure that you have set it to ANY.

Simon.

This is what I receive when I enter in 'whatismyip' in the Domain field and select ANY:

. here is the nslookup result for 12.*.*.0 from server localhost, querytype=PTR :

 DNS server handling your query: localhost
 DNS server's address:      127.0.0.1#53
 
 ** server can't find *.*.*12.in-addr.arpa: NXDOMAIN
 Thanks :)

You have no PTR record. You need to speak to your ISP and get it corrected.

Simon.

Clarification-would it be our ISP or the company that responds as 'nameserver' when I do my DNS query?
When I run that--it shows 'nameserver' as the same co that hosts our website
mx record points to our current firewall/email filter co.(whcih we are getting rid of)

It is whoever provides you with the IP address. They may well try and tell you to go and see who hosts the domain - at that point ask to speak to someone who understands how the internet works.

Simon.