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Can't telnet into Exchange Server

Posted on 2004-04-18
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Last Modified: 2012-06-27
Hi recently I setup an SBS 2K3 Server at my office.  It all setup mostly well (Except my companyweb website which didn't get installed and that's even with the new CD3 that they sent me but that's another story).  Anyhoo we have a registered domain name say www.abc.com and it's setup to redirect any mail to the the domain to a mailbox that the exchange server is currently popping from no problems.  Anyhoo I want to change the MX record for my domain to go straight to my exchange server.  But before I do that I wanted to make sure that my exchange server was available.  So I tested with telnet.  When I "telnet www.abc.com 25" the screen pauses for a little bit and then brings me back to a dos prompt.  Does this mean my server is not available to the internet (SMTP wise).  I can successfully get terminal services, remote desktop, outlook web mail and VPN.  Why can't a simple port 25 port forward work?????

The server has two network cards

Internal is : 192.168.1.254 and External is : 192.168.0.3

I have a Netgear DG834 Router that is 192.168.0.1 and I have set port forwarding for all the usual stuff for remote access INCLUDING Port 25 all to 192.168.0.3

The router has the latest firmware installed.

Anyhoo I noticed if I telnetted locally on the server I can "telnet 192.168.1.254 25" and get the blabber at the top.  If I "telnet 192.168.0.3 25" the PC pauses for a little bit and then brings me back to a prompt just like when I try from the net??

Somethings' amiss.  Do I need to sort of bridge the two adaptors in my server?

Please help

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Question by:tiggerthegrr
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rhandels earned 250 total points
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Hi,

So you figured out for yourself that the SMTP wasn't working.

Yes, you do need some kind of a bridge. You can do this by using a static NAT rule. These are using to Address Translate an external address into an internal address.

This explains why telnetting 192.168.1.254:25 works. This is how it should go.

People mail to your www.abc.com. This is rerouted to your external ip address of 192.168.0.3 via DNS. You should set up a NAT rule that whenever there is a port 25 request to your external ip address 192.168.0.3, that it is renamed after 192.168.1.254. Then it will work, cause they set up a connection to the 192.168.1.254 address. I do think you need some extra software to do this.  I know RRAS (Remote Access Server) can do this, it's a build in function in Windows 2000 Server. You can also try and use proxy, but it will cost ya a buck or two....

Hope this helps
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by:rhandels
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Why the c grade??? Wasn't the right solution??? If you have some questions, you can ask them....
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by:tiggerthegrr
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Thanks for the input rhandels.  I didn't know where to look and your suggestion to look into the Routing and Remote access was the right place.  I turned on basic firewall and then port forwarded from the 192.168.0.3 interface on port 25 to 192.168.1.254.   I stopped and restarted the service just to be sure.  Then I was able to telnet into smtp.  Thanks again.

btw i tried to telnet locally telnet 192.168.0.3 and it still went to the command prompt.  It's not really a problem since it works on the net.  Any suggestions why telnet doesn't port forward locally???

Regards
tigerthegrr
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by:rhandels
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So th answer was correct, but you gave me a C grade... :(..... Oh well, as long as the problem is fixed eh...

I think that Telnet actually is kind of a dumb program. If you say that you would like to telnet to ip address 192.168.0.3, it does so. I believe that Telnet (and even all tcp/ip related traffic) doesn't actually know that the other ip address exists, only if you say that he has to look for another ip address (so Nat it), it will do so.

Computers only do what you tell them to do.
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by:tiggerthegrr
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Hi
I gave a C coz you suggested to look at Routing and Remote access but I had to fiddle around a bit to work out what to do.  I give A's to step by step instruction and B's if people point me to a tutorial or further information.  I thought C was fair as you suggested the correct thing but then left it at that.  I don't mean to offend coz you helped me but I guess to be fair to the grading system I judged based on the quality of help I've gotten in the past say from Kidego or Vahik who send a whole encyclopaedia and go out of their way to educate the n00b that i am.

Thanks for your input again.

tiggerthegrr
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by:rhandels
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Hi,

Thanks for the explanation, but i don't really think your a n00b ;)... Else you would be asking n00b questions (and this wasn't).... ;) LOL

I will try to give a little bit more info the next time, but i normally try to find out as quickly as possible what the problem is, and then help somebody a bit further, else i'm blabbering a lot of rubbish.... ;)
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