Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 575
  • Last Modified:

Can't receive external email

I have searched through many of the postings on EE and have had no success at resolving my issue, however, they have helped to maybe fine tune the configuration. So, now it's my turn to ask the experts.

I have Exchange Server 2003 running on the same computer as SBS2003. There are no other server installations on the network. We have DSL access through a Cisco 8xx DSL router.

I want to be able to receive email directly from the internet, but before going live with our real domain emails currently hosted by our ISP through aliases, I decided to test a configuration with another domain name we have registered and are using for external access to our internal web. We have one external static IP address. We have two NIC's on our server box -- one connected to the WAN (via the Cisco router) and the other to our LAN.

I have verified the following configurations (found via various postings to EE):
1) The host and MX records appear to be appropriately setup at the external DNS. DNSreports.com correctly resolves these records. However, when checking the domain name, DNSreport.com reports there is a time out error when connecting to our mail server.
2) I have setup a reverse lookup record at our ISP for our "alternate" domain from our external IP.
3) I am forwarding traffic for port 25 on our router to the ip address of our internal exchange server.
4) In the SMTP virtual server, I have anonymous access checked under access authentication and I have "all except the list below" checked for computers allowed connection. There are no computers listed below.
5) I use GFI Essentials as a spam filter on the Exchange server. I have disabled the service, but no effect on successfully receiving emails.
6) I can telnet to our mail server on port 25 internally using both the internal ip address as well as its global name (ie, mail.externalname.com).
7) I cannot telnet to our mail server externally. I get a blank command screen.
8) I can successfully send an email internally to a user at this test email domain.

Help!
0
clcarlson
Asked:
clcarlson
  • 11
  • 8
1 Solution
 
susanzeiglerCommented:
When you say that host name appears to be resolving correctly, you are saying it is resolving to the external IP address of the router, correct? Can you telnet on port 25 using external IP address instead of the host name? If not, then it sounds like there may be port blocking going on externally to your network. Does your ISP need to open up port 25 inbound on their firewalls (many ISPs are filtering that port now)? Have you tried sending from multiple external locations--since you say that DNSreport is timing out, I'm doubting that blocked outbound SMTP from the testing locations is the issue.

There's a start. I highly doubt internal DNS is causing issues, but that would be the next thing to examine
0
 
clcarlsonAuthor Commented:
Yes, you are correct that it is resolving to the external address of the router. I cannot telnet on port 25 to the external ip of the router or the host name.

I confirmed with my ISP that they do not block any ports.

By trying to send from multiple external locations, I have also tried sending several emails from my personal email account which is through a different ISP. It has not been successful. The most recent failure report states: "451 4.4.1 reply: read error from mail.testdomain.com"
0
 
m298908Commented:
Place a switch on the wan so that the external server NIC and the inside router NIC are on it.  Add a test machine to the switch and give it an address on the network.  telnet to port 25 of the external sbs server NIC.  does that work?

0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 
susanzeiglerCommented:
That's a good test since chances are high that it is the external interface that is not getting through.

"3) I am forwarding traffic for port 25 on our router to the ip address of our internal exchange server."

This should be the IP of the external NIC--please verify that it is indeed that and not the internal NIC IP.

When you did the set-up of Exchange,did you use the set-up wizard. When using the wizard, it should walk you through configuration of the additional SMTP connector for the external IP.  That is the next place to look. In ESM, look to make sure that there are two SMTP virtual servers.  (Servers > yourservername > Protocols > SMTP). One of them should be configured with the LAN IP and the other with the private WAN IP. If there are not two, then this is at least part of the problem. Exchange needs to know to listen on both interfaces for SMTP traffic.

Now for the other question. Why was Exchange 2003 added to the SBS2003 server. The version of Exchange that comes with it is the standard version. I am also wondering if there could be an issue here--are there two installations of Exchange on that server (one would be incomplete)?
0
 
clcarlsonAuthor Commented:
In response to m298908's suggested test, I need some clarification and then I'll try to do it in the am when I'm not disrupting the workflow. I'm not clear on where you want me to put the switch.

Are you suggesting:
1) DSL router ---> WAN NIC ---> WAN port on switch and LAN port on switch ---> LAN NIC (with a workstation also plugged into one of the switch LAN ports)? or
2) ?
0
 
susanzeiglerCommented:
What they were trying to say was that you need to test the external NIC of the server on the inside of the router. This will eliminate the router/ISP filtering from the picture and will show whether the Exchange server accepts connections inbound on port 25 on the external interface. Your internal tests show that the Exchange is accepting SMTP connections on the internal NIC only.

                                         |---> WAN NIC
DSL Router ---> Switch/hub |
                                         |---> Workstation

                                         
0
 
clcarlsonAuthor Commented:
Ok, thanks. Now, I will also respond to your previous comment which I had intended to get to earlier, but the day's been quite hectic.

Actually, I at first had it pointing to the external NIC as are my other ports, but that wasn't working. So I thought maybe I should try the internal NIC. Neither works, but I do get different results: When forwarded to the external NIC, the message was something similar to "connection closed before I received all my data." With it forwarded to the internal NIC, it's a "timeout " message.

This may be the problem as I only have one SMTP virtual server. Yes I did use the wizard, but at the time I initially set everything up, I was using POP accounts with our ISP and retrieving the email through the POP connector. When I decided to try to see if I could set up receiving email from the internet, I used the wizard again. However, it did not set up an additional SMTP server. Actually, I'm not sure what it did, if anything. So, it sounds as though I need to create an additional SMTP server. Since the existing one is named "Default SMTP Server" can I rename it without creating havoc through the system? This "Default SMTP Server" is pointing to the internal NIC which is why I thought maybe I needed to forward port 25 to the internal NIC.

Now as to your last question. I guess I assumed I had Exchange 2003. It is the version that came with my SBS2003 package which was a factory install. No, there have not been multiple installations of Exchange Server, only inexperienced tweaking :).
0
 
clcarlsonAuthor Commented:
An additional note, I notice when trying to create an additional SMTP virtual server, the only ip options I have are my internal NIC and unassigned.
0
 
clcarlsonAuthor Commented:
Good morning. Set up test as suggested as follows:

                                         |---> WAN NIC (ip 192.168.17.2)
DSL Router ---> Switch/hub |
                                         |---> Workstation (ip 192.168.17.3)

When I try to telnet on port 25 to ip 192.168.17.2 from the workstation, I get a connection lost result.

I hope this was the right configuration and is telling us what we want to know which is that something is not configured correctly.

0
 
susanzeiglerCommented:
Yes. And it is indeed that a second virtual connector needs to be set up. Default is ok to leave as is. See if you can re-run the SMTP wizard.

Here's a really good article on how the wizard works when you set it up with two NICs:
http://www.msexchange.org/tutorials/Using_Exchange_2003_Mail_Wizard.html

The key item is the following:
"When you configure the Internet Mail Wizard on a server with two NICs, the wizard configures the Server as follows: The wizard creates an additional SMTP virtual server on the Exchange server. It configures Internet mail delivery in as follow:

"The Internet Mail Wizard guides you through the steps of assigning the internal IP address to the default SMTP virtual server on which it creates the SMTP connector to send outbound mail. You assign the internal IP address to this virtual server so that only internal users on your internal network can send outbound mail.

"To configure the server to receive Internet mail, the wizard guides you through the process of assigning the Internet IP address to the external SMTP virtual server. You assign an Internet IP address to this virtual server because the external Server must  be able to connect to the SMTP virtual server to send Internet mail."


Even if you can't rerun the wizard, you can create the additional SMTP connector and assign the external IP to it. Note that the default is supposed to be the internal IP:)
0
 
clcarlsonAuthor Commented:
Thanks, I'm out of town until Thursday. I'll work on this when I return.
0
 
clcarlsonAuthor Commented:
Ok, so I'm back and have read through your comment and the link. It appears, however, that my Exchange Server doesn't seem to recognize that it's a dual-homed server.

When I manually create an additional SMTP virtual server, the only ip options I get are the internal NIC's ip address and 'all unassigned'.

When I run the wizard, my Exchange Server passes the prereq test. When I try to proceed from the Select email functions window, I get the following message: 'To send internet e-mail, the selected server cannot be a bridgehead server" and it won't proceed.

Is there somewhere else I need to identify the external NIC?
0
 
susanzeiglerCommented:
Hmmmmm, do you see both NICs in the network settings (you should).

On the default SMTP connector, it should only be set to send email--not to receive it. The new connector will receive mail only. The bridgehead (when dealing with a single server) is always set to the sending server.
0
 
clcarlsonAuthor Commented:
Yes I can see both NICs in network setting.

When you say 'default SMTP connector', do you mean connector or virtual server? Actually, I don't see where to indicate not to receive email in either connector or virtual server.
0
 
susanzeiglerCommented:
Yes, I meant default virtual server--was thinking in a pre-2003 world today.

You can designate that on the initial run of the wizard. I'll see if I can do some looking through some material at home and try to determine how to get Exchange to recognize the second NIC.
0
 
clcarlsonAuthor Commented:
Well, have a good weekend then. Thanks for sticking with me.
0
 
clcarlsonAuthor Commented:
I have finally succeeded in getting my email server to accept external email. Now, I can't get the server to deliver the email to the intended recipient. I do have multiple domains. I have added the email address to the user's account and I have the domains listed in the default recipient policy. However, the messages are just sitting in the queue. What have I overlooked?
0
 
susanzeiglerCommented:
Can you determine which queue the messages are sitting in? There are several inbound queues.

I assume you have done a full stop and start on the services and that the Information Store service is running.

Are there any error messages in either the SMTP log or in the event viewer that help to see why the messages are not getting delivered.
0
 
clcarlsonAuthor Commented:
It was as simple as restarting IIS. Thanks.
0
 
susanzeiglerCommented:
:) Wonderful. Am so glad you got it all working!
0

Featured Post

Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

  • 11
  • 8
Tackle projects and never again get stuck behind a technical roadblock.
Join Now