I wanted to thank "SpacemanSpiff", who actually perfectly answered the question, by helping me discover a wonderful website called Google.
Though I'm using it in french (not the 5th link for me...), I was able to find a website listing the requirements of DirectAccess. The rest of the article is also very interesting.
The following list of DirectAccess requirements comes directly from Microsoft TechNet:
- One or more DirectAccess servers
running Windows Server 2008 R2 with
two network adapters: one connected
directly to the Internet, and a
second connected to the intranet.
- On the DirectAccess server, at least
two consecutive, public IPv4
addresses assigned to the network
adapter that's connected to the
- DirectAccess clients running Windows7.
- At least one domain controller and DNS server running Windows Server
2008 SP2 or Windows Server 2008 R2.
- A public key infrastructure (PKI) to
issue computer certificates, smart
card certificates, and for NAP,
- IPsec policies to specify protection
- IPv6 transition technologies available for use on the DirectAccess
server: ISATAP, Teredo, and 6to4.
- Optionally, a third-party NAT-PT
device to provide access to IPv4-only
resources for DirectAccess clients.
At least no protocol nor cabling limitations.