Our internal network was set up several years ago with the 192.168.0/24 address space. However, it seems that virtually every SOHO router made has this address space as its default, which makes it impossible for the users to connect to the corporate network (we are using Checkpoint NG with AI and the SecuRemote 56 client running IPSec) unless this default is changed -- which some routers do not allow, and even if they do the user does not know how to do it.
We are considering changing our network address space to some less-common range, e.g., 192.168.131/24 (to choose a random number). However, this is a major undertaking.
What solutions are available, if any, where one can have the foreign and corporate networks use the same address space but be able to communicate with both? To use a particularly thorny example, say that a foreign printer and the corporate e-mail server had the same IP address but different names? Is there any way for the VPN client to determine to which network to send which traffic?
If there is no easy solution, what alternatives are there (changing VPN technology -- maybe to SSL?) to rebuilding our network?