Configure RDP through to Windows Server 2008 on Secure Computing SG560 Firewall

Hello,

I run a Secure Computing SG560 Firewall.
I am replacing our Windows Server 2003 Terminal Server with a 2008 Terminal Server.
Within our firewall rules, I have created a Definition and given the definition a name of the server plus the servers IP.
In Packet Filtering, I have created a rule, given it a descriptive name, set the action to Accept,
Type: forward
Incoming Interface: any
Outgoing Interface: any
Source Address: A defined IP address
Destination Address: The defined IP address of the terminal Server
Services: RDP

Upon trying to RDP in, I get the following message: This computer can't connect to the remote computer.

So I enable logging, I can't even see the attempt in the log.

As some troubleshooting, I have changed the destination back to the old Terminal Server. Straight away, I get in and within the logging on the SG560 I can see the attempt.

Internally, I can RDP to the 2008 Server with no problem.
I read a KB stating to recreate the connection under Terminal Services Configuration in which I have.

It has made no difference. I have tried a few different version of RDP with the same problem when external but works fine internally.

Thanks

paulwozAsked:
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tstritofConnect With a Mentor Commented:
Hi,

I'm guessing this has to do with your internet firewall. However, empty logs are confusing element.

Another thing that confuses me a bit is the setup of what you call "Definition". I interpret this term as means of creating a group of internal resources serving some purpose and using that definition when specifying firewall rules. I don't see how this is used if you set your firewall rule simply by explicitly setting the IP address of destination in firewall rules. Could you please explain how you use this definition in the setup of firewall rule?

Basically (and I'm guessing here) the rule you've set up only allows/disallows the traffic through firewall based on source/target IP address and TCP port used. However, firewall rules aren't normally used for routing so I believe there should be some other rule (usually called NAT forwarding) that tells your router that traffic on port 3389 coming from internet for public IP address must be routed to a certain internal IP address. I'm guessing again that you have such forwarding rule and that it still points to the W2K3 server. So basically, your traffic always routes to W2K3 server, only your firewall rule drops it when you change destination in it to allow only IP of W2K8 server.

Regards,
Tomislav
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tstritofCommented:
Hi,

since by your post you don't have a problem with your internet facing firewall nor the ability of new terminal server to yccept RDP connections you might have a problem with Windows Firewall on your new terminal server. Check the inbound rules and make sure that the IP addres (or network) from which you connect externally isn't rejected by WF on TS.

Regards,
Tomislav
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paulwozAuthor Commented:
Oh Sorry, forgot to mention. Firewall is off with RDP as an exception.
I then disabled the firewall service with no joy also.
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tstritofCommented:
Are you using standard RDP port number (3389) for external access? What port is your firewall listening on for external RDP connections?

What do you mean when you say that you disabled the firewall service? Have you disabled the firewall in setup or stopped the service altogether?

Also - can you please confirm the following:

1) When accessing RDP externaly, with absolutely nothing changed other than destination IP on your external firewall everything works fine when destination IP in forward rule points to W2K3 server but stops working when destination IP points to W2K8 server.
2) In both cases the destination IPs are internal to your network and you can access your W2K8 server through RDP by that same IP when connected directly to your internal network.
3) You are not using any custom setup or records (like SRV records) in your public domain DNS to redirect RDP traffic to custom address/port.
4) Your firewall and your RDP client don't require that your terminal servers authenticate through certificates or some other way?

Regards,
Tomislav
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paulwozAuthor Commented:
Hi tstritof.

I am using 3389

I have done all of the above with the firewall. Firstly I turned it off via control panel.
Then stopped the firewall service
Then disabled the firewall Service.

Answering your questions:
Q1: Yes that is correct, works fine with W2K3, not 2K8 with only the dest IP changed.
Q2: I can definitely connect to it fine internally with the same IP as I set in the dest IP
Q3: No custom records from what I know and it definitely is listening on 3389. I confirmed via checking the registry.
Q4: Not at all.

Cheers

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paulwozAuthor Commented:
tstritof,

Thank you so much!

You were spot on, I was configuring via Packet Filtering and creating a "definition" to the server.

As soon as you mentioned NAT, I added it there and low and behold it worked!

Thank you so much!
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tstritofCommented:
:) Glad it worked.
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