Restricting remote ssh key commands with a regex?



I am used to restricting remote ssh key commands in the auth keys file but I have an instance where it would be necessary to define a very nice tight regex to allow me to specify a command where only the IP address changes and I cannot predict the IP address in advance.

Any ideas, can this even be done in this way?

I am running various versions of openssh, mainly 4.3 and 4.7, but right up to 5.1.

-h

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Hari Sekhon
Always open to interesting opportunities
http://www.linkedin.com/in/harisekhon