I'm having a little problem with configuring the firewall on my server. I only want a specific range of IPs to be able to access specific ports. For example, I'm having alot of password attempts to some of my servers, so I want to make it more safe by only allowing incoming connections from a specific range of domain.


My IP is usually adsl-324-4.somecompany.com so I want to allow *.somecpompany.com to connect, as my IP is dynamic. That would get rid of alot of attempts to hack into my servers. But I have no idea how to mask a domain like that for the firewall. How could I for example allow all incoming connections from *.is?



You'll need to first find out what range of IPs you're getting your dynamic IPs from. A /24?

Then you can add a rule for that range to allow access to whatever you want in. RDC? 3389

Here is a quick overview of the firewall. Let me know if you need more help adding the rule.


  • Hi again. I don't really mind the range, but rather I'd like to allow the whole *.somecompany.com as a rule. Let's take simnet.is as an example. How would you make a rule that allows *.simnet.is as incoming connections? Thanks! :-) – Jon Jul 1 '09 at 9:08

It would be more secure to set up something like CopSSH, and then create an SSH tunnel. Then you could block all inbound ports for RDP, but open up another port like say 6500 (configure that in copSSH sshd config file).

Once that is done, you can use Putty to create a connection to your server, then in putty set up an ssh tunnel mapping your local port 3389 to the remote port 3389. Then to connect with RDP, you just make the putty connection and RDP to localhost.

It takes a bit more setup, but if you are really concerned about security this is a better route to take.

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