I have a central office and 2 remote offices.
All three have an ISA2004 server. The central office connects to each of the 2 remotes over a site-to-site vpn.
I want to upgrade the central office to ISA2006.
Can I have an ISA2006 with 2 site-to-site VPN links, when the 2 remote sites are still running ISA2004?