Company web and Exchange only work internally

rrincones used Ask the Experts™
Suddenly, the company web cannot be accessed from outside the network and we can only receive emails internally.  We can send out emails to external contacts, but cannot receive mail from them.  

The companyweb can be accessed from within the network.

Here is our setup.

Microsoft Small Business Server 2003

Our ISP is Time Warner, Road Runner.  

Our account is setup as DHCP.

The server has two nic cards, one for broadband is connected to Time Warner modem, the other to the network switch.

The server is using a software from Dynamic DNS that updates their host file with the new IP whenever it is changed.  I have verified that it is up to date.  I pinged the domain and receive a response from the IP currently assigned.

I have verified that the websites in IIS are running.

Not sure where to start troubleshooting.
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James HIT Director

Try to telnet to your exchange servers' external address:

open a command prompt and type:

telnet 25 (use your OWA address) and see if you get a response.
WORKS2011Managed IT Services, Cyber Security, Backup

go to Shields Up, click here to scan the firewall and verify the correct ports are open.
WORKS2011Managed IT Services, Cyber Security, Backup

you'll click on "proceed" then "all service ports" or you can select one port individually "user specified custom port probe"


I received message connect failed.  How do I verify if I used the correct owa address?
WORKS2011Managed IT Services, Cyber Security, Backup

are you testing inside your network or out? Inside try this https://servername/exchange outside you'll try 

test your dns by clicking here, post the results.
WORKS2011Managed IT Services, Cyber Security, Backup

here are some things you can try

- on the server run iisreset from a command prompt to reset IIS

- run ipconfig /flushdns on the server and workstation you're testing from

- on the workstation run ipconfig /registerdns


i was testing outside.  I ran the test you suggested. Here are some results.

Your MX records that were reported by your nameservers are:


[These are all the MX records that I found. If there are some non common MX records at your nameservers you should see them below. ]  
 Different MX records at nameservers Good. Looks like all your nameservers have the same set of MX records. This tests to see if there are any MX records not reported by all your nameservers and also MX records that have the same hostname but different IPs
 MX name validity Good. I did not detect any invalid hostnames for your MX records.  
 MX IPs are public OK. All of your MX records appear to use public IPs.
 MX CNAME Check OK. No problems here.
 MX A request returns CNAME OK. No CNAMEs returned for A records lookups.
 MX is not IP OK. All of your MX records are host names.
 Number of MX records OK. Looks like you only have one MX record at your nameservers. You should be careful about what you are doing since you have a single point of failure that can lead to mail being lost if the server is down for a long time.  
 Mismatched MX A OK. I did not detect differing IPs for your MX records.
 Duplicate MX A records  OK. I have not found duplicate IP(s) for your MX records. This is a good thing.
 Reverse MX A records (PTR) Your reverse (PTR) record: ->
You have reverse (PTR) records for all your IPs, that is a good thing.  
WWW  WWW A Record Your A record is: -> -> [  ]

[Looks like you have CNAME's]  
 IPs are public OK. All of your WWW IPs appear to be public IPs.  
 WWW CNAME OK. You do have a CNAME record for CNAME entry also returns the A record for the CNAME entry, which is good.
Managed IT Services, Cyber Security, Backup
how about ports on the firewall, are they showing open?

- 25 - Simple Mail Transfer Protocol
- 80 - HTTP Web
- 443 HTTPS
- 4125 RWW
James HIT Director
Did you make any changes to your Time Warner account? I am assuming you are using them as a smarthost.

Your response that you cannot communicate through telnet suggests that there is something blocking access to your server. Review firewall/router rules and ensure all necessary port are opened.... see WORKS2011 post for port numbers.


The problem was with Time Warners modem.  Somehow the settings reverted to original installation.  The firewall and nat was enabled.  I had them set it up as bridged and all was back to normal.

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