New to the Firewall/Router world...need help

[350ztn]

Batism by fire...
A customer is adding a location and expanding another. The previous IT guy left and now it is my problem to expand the IP's and subnets. From what I know they have the same IP scheme 10.245.1.x and subnet at main building is a 128 and 240 and the other 2 locations. One offsite location is being expanded and will need a larger IP range, more than the 240 will allow (16 IP's, right?) they need like 25 and expansion room. The new location just needs to be configured and probably a 128 subnet. So here is my question... Instead of trying to redo subnets to keep everyone on the 10.245.1.x scheme and squeeze every available IP addres I can find out without much room for expansion. Can I redo the IP addressing for the remote locations...10.245.2.x, 10.245.3.x, and 10.245.4.x all with .128 subnets. Does this present any issues with routing? The customer uses 506E Pix for the encryption and for the basic routing from what I understand.
Thanks for the help and I'm open to suggestions

 

[lgarner]

Sure, and it makes sense to me. But, I'd use a /24 at least for each office. No need to restrict yourself. You have over 16 million addresses available in the 10 network.

Routing is no different. You have several separate networks now, you'll just number them differently in the new setup.

 

[350ztn]

by doing a /24 at each of the offices except for the main office which is a /25 which I will leave alone that will not present any problems with routing. I know all branch offices go back to the main office for internet access, does the larger subnets than the main office present any issues there? I just want to make sure there isn;t some special routing commands I need to do to make these changes.