[powershell] Powershell remoting with ip-address as target

I successfully enabled PSRemoting on my Server 2008 R2. I'm able to do a remote-pssession from within the same network using the hostname as target.

I'm failing when I try to use the IP-Address as target from any computer (within the network or from another network (for example via VPN)). I want to be able to use remoting through my VPN connection where I have to use the IP-Address since the hostname can't be resolved.

I don't want to add names into my hosts-file because there are a few other servers at our clients' that have the same dns-name and I don't want to remove and insert the name-ip-address-association again and again.

I hope someone can tell me how to allow the psremoting-target to be called via IP.

Edit: To be more specific, I want to be able to run this:

Enter-PSSession -Computername 192.168.123.123 -credentials $cred 

But I'm only able to run that command if I pass a hostname to "-Computername"

Edit2:
I'm getting following errormessage when I try to login using the ip instead of the hostname (from the internal network):

Enter-PSSession : Connecting to remote server failed with the following error message : The WinRM client cannot process
 the request. Default authentication may be used with an IP address under the following conditions: the transport is HT
TPS or the destination is in the TrustedHosts list, and explicit credentials are provided. Use winrm.cmd to configure T
rustedHosts. Note that computers in the TrustedHosts list might not be authenticated. For more information on how to se
t TrustedHosts run the following command: winrm help config. For more information, see the about_Remote_Troubleshooting
 Help topic.

Edit3:
I know about the trusted-hosts setting of WSMan, but that doesn't seem to be the problem. It is already set to "*" (I did that right after enabling remoting), but I still can't connect to that server using the ip as target-computername, but I'm able to connect using the hostname as target-computername. Seems like there's something like the binding in IIS that prevents the listener to listen on requests that target the ip-number instead of the hostname. But IIS isn't installed. I don't know where to look for such a setting.

Update 2011-07-12:
Okay, I think that trustedhosts-setting is not the problem because I CAN connect from our DC via hostname but not if I use the ip-address of the destination for the computer-param.
I think, the problem must be the listener. Maybe the listener takes no requests that were targeted to the destination-ip instead of the destination-hostname. But I don't know how to change that.

The guys have given the simple solution, which will do be you should have a look at the help - it's good, looks like a lot in one go but it's actually quick to read:

get-help about_Remote_Troubleshooting | more

I test your assertion in my infrastructure the IP address is not the problem the following works for me :

PS C:\Users\JPB> hostname
JPBCOMPUTER
PS C:\Users\JPB> Enter-PSSession -ComputerName 192.168.183.100 -Credential $cred
[192.168.183.100]: PS C:\Users\jpb\Documents>
[192.168.183.100]: PS C:\Users\jpb\Documents> hostname
WM2008R2ENT

If you try to work accross a VPN you'd better have to have a look to the firewall settings on the way to your server. Installation and Configuration for Windows Remote Management can help you. The TCP port WinRM is waiting on are :

WinRM 1.1 and earlier: The default HTTP port is 80.

WinRM 2.0: The default HTTP port is 5985.

Edited : According to your error can you test this on youclient computer :

Set-Item WSMan:\localhost\Client\TrustedHosts *

On Windows 10 it is important to make sure the WinRM Service is running to invoke the command

* Set-Item wsman:\localhost\Client\TrustedHosts -value '*' -Force *

For those of you who don't care about following arbitrary restriction imposed by Microsoft you can simply add a host file entry to the IP of the server your attempting to connect to rather then use that instead of the IP to bypass this restriction:

Enter-PSSession -Computername NameOfComputerIveAddedToMyHostFile -credentials $cred 

On your machine* run 'Set-Item WSMan:\localhost\Client\TrustedHosts -Value "$ipaddress"

*Machine from where you are running PSSession

Try doing this:

Set-Item WSMan:\localhost\Client\TrustedHosts -Value "*" -Force