Multiple IP address while first IP is given by DHCP (Windows 7)


Problem: I have 2 computers connected (via a switch) to the Internet. They both have DHCP addresses (Both IPv4 and IPv6) handed to them.
My ISP have multiple nets that get handed out and sometimes my client (hereafter refered to as C) and my server (hereafter refered to as S)
gets on different subnets.

Note: Both C and S are Windows 7 machines.

I want to use windows file sharing between these machines and as long they were on the same subnet it was all good. But when I rebooted either machine I
sometimes get on different subnets and then I couldn't get the Windows File Sharing to work.

Solution I found good was to

Set up the machines to use IPv6 for the local File Sharing.

Howto on S:
1. Control Panel -> All Control Panel Items -> Network and Sharing Center -> Click your NIC -> Properties -> Internet Protocol Version 6 (TCP/IPv6)
"Use the following IPv6 address" -> Type fc00::1 (The IPv6 counterpart of IPv4s private network is called Unique local address)
2. Click "Advanced" -> Uncheck "Automatic metric" -> Enter "9999" in the box

Howto on C:
1. Control Panel -> All Control Panel Items -> Network and Sharing Center -> Click your NIC -> Properties -> Internet Protocol Version 6 (TCP/IPv6)
"Use the following IPv6 address" -> Type fc00::2
2. Click "Advanced" -> Uncheck "Automatic metric" -> Enter "9999" in the box

The UNC path to the machines are different from the IPv4 version.
IPv4: \\<IPv4>\<shared folder> while in IPv6 they the look like:
IPv6: \\<IPv6 but replace ':' with '-'>.ipv6-literal.net\<shared folder>
(See this Wikipedia link for more info: http://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names)

Example: If you configured the machines the same way I did in the HOWTO the UNC to ther server share would be:
\\fc00--1.ipv6-literal.net\<shared folder>

I hope this helps! You can contact me on win7_multiple_ips (a) hardingonline DOT se