NLA doesn't recognize domain on my local interface

HI all,

I have DC1 ( holds fsmo role ) and DC2. ( 2008 r2)  - win 2003 functional level

If I shutdown DC1, then restart DC2, then local area connection of DC2 goes to unidentified network.

I added the domain name to "DNS suffix for this connection" in the local area connection. After disable/enable the local area connection, it recognized the domain. After reboot of DC2, again same issue and can't get it back to the domain.

Is it expected behavior ? Or how to change NLA behavior ?

thanks