Answer by Brian for Cannot disable IPv6 components on exchange server without breaking exchange

Instead of disabling ipv6 another option is to modify the prefix policies so IPv4 addresses are used over IPv6 when available.

C:\>netsh interface ipv6 show prefixpoliciesQuerying active state...    Precedence  Label  Prefix----------  -----  --------------------------------        50      0  ::1/128        40      1  ::/0        30      2  2002::/16        20      3  ::/96        10      4  ::ffff:0:0/96         5      5  2001::/32

In the list above the lines with labels 3 and 4 represent IP4 compatibility listings. If you increase their precedence they will be preferred.

C:\>netsh interface ipv6 set prefix ::/96 60 3Ok.C:\>netsh interface ipv6 set prefix ::ffff:0:0/96 55 4Ok.

Now if you try to connect to hosts that return both IPv4 and IPv6 addresses from DNS the IPv4 ones will be preferred.