I have Windows Server 2008R2 with several Windows Server 2008R2 VMs in Hyper-V. Hyper-V guests have internal network which are bound to my external (host network) via RRAS.
One of the guests is domain controller with iSCSI target installed. Other guests - some are members of domain, some are not are - are iScsi initiators. Everything works fine as long as external host network is connected to internet (or perhaps have IP address - did not test no internet connection with static IP option) when iScsi target is trying to connect/login to initiator. If host network is disconnected (e.g. guests don't have internet access), those stuck on Reconnecting stage. If I disconnect from internet when targets are connected, everything works fine.
I tried to create another private network for iScsi but it did not help.
P.S. This is obviously not the production setup - I have lab on my laptop.