I find that the host-only networking does not work since I upgraded to RC2. I reinstalled the Parallels Desktop, but the problem is still there. On host side: In network pane, I can see "Parallels Host-Guest Adapter", but IP is not assigned from the DHCP server. On Parallels side: In Preferences>DHCP, when I try to change the scope, an error message appears as "Scope renew failed! Unable to open file, containing DHCP scope information and daemon pid." On guest side: An IP address: 192.168.2.30 is assigned, which I believe is out of the scope of the DHCP server. The networking is not activated.
I repeated for several times reinstalling Parallels, abondoning the preference file, and restarting the host OS, and eventually the DHCP server starts to work.
I'm having this same problem now too. I cannot get host-only network working, and if I try to modify DHCP I get teh "Scope renew failed!..." error. I believe this issue is related to what is written in this post. If I run the given command 'ps axuww|grep prl_dhcpd' I do NOT get the /Library/StartupItems/Parallels/prl_dhcpd item listed. If I run the given command to launch the item ('sudo /Library/StartupItems/Parallels/prl_dhcpd') I then do get the item, however I can see in my console log that my system is repetedly getting mDNSResponder error messages in relation to prl_dhcpd, and though my VM gets an IP address, I still cannot ping external IP addresses. However, after prl_dhcpd is running, I no longer get the error from above (which is why I believe it's related). But, if I then proceed to reboot my Mac, I again end up without the /Library/StartupItems/Parallels/prl_dhcpd item listed (and when I proceed to try to launch the process, I again get the mDNSResponder timeouts). Essentially it appears I have no easy fix for this problem asside from not using host-only networking...
If your router is issuing IP addresses in the 192.168.2.x range, host networking with sharing will not work. Even though Parallels DHCP configuration defaults to 10.x.x.x addresses it ignores those values and uses an apparently hard coded range of 192.168.2.x. I reported this to Parallels via their "Report a Problem" interface but never received a response. Reconfigure your router to issue IP addresses in some other subnet. i.e. change the third number to 0 or 1 or 3 or anything other than 2. Once I did this host networking with sharing has worked solidly for me.
