Question : Two 2008 R2 Domains on Same Subnet - is this ok?

Hi there - we currently have a single domain 2008 R2 network with Win7 clients working really well. A second company is being purchased and added to the network. Would like to share the Internet between the two companies and allow access to resources across both domains (via a trust). Company needs to stay seperate as the marriage is temporary:)   Can we have the two domains share the same subnet without issues - seems the least amount of work from network reconfig perspective?  Or I am best to buy extra gear try and establish two vlans and keep things seperate?

I can think of a few challenges with everything on the same subnet including DHCP and serving up the right DNS server to the appropriate client.  Any guidance would be greatly appreciated.

Answer : Two 2008 R2 Domains on Same Subnet - is this ok?

Yes. YOu can create another DNS Zone.

http://www.zdnetasia.com/creating-a-forest-level-trust-relationship-in-windows-server-2003-62032531.htm

That will help you with the trust in your forest.
Yes.
Yes