Platform SDK: DirectX

DirectX 5.0-DirectX 6.0 Cross-Compatibility Reference Chart

The following chart shows which versions work with each other, assuming there are only two computers, and the firewall referred to is physically the same firewall for both (that is, both the client and host are behind the same firewall). Note that DirectX 6.0 means "DirectX 6.0 or later."

  Internet DirectX 5.0 Host DirectX 5.0 Host Behind Firewall Internet DirectX 6.0 Host DirectX 6.0 Host Behind Firewall
Internet DirectX 5.0 Client yes no yes no
DirectX 5.0 Client behind firewall no yes no yes
Internet DirectX 6.0 Client yes no yes yes
DirectX 6.0 Client behind firewall no yes yes yes

The chart still holds true for more than two computers if the session is client/server. If there are more than two computers, the session is peer-to-peer, and there is a firewall involved anywhere, then all computers must be using DirectX 6.0 or later.