Do you have a route for 10.7.2.10? Are you able to ping it? Do you have any filters, such as a Loopback or interface filters applied? You may want to set a trace to see how JDHCP is handling the request.
set system processes dhcp-service traceoptions file JDHCP set system processes dhcp-service traceoptions file size 5m set system processes dhcp-service traceoptions file files 2 set system processes dhcp-service traceoptions flag all
Feel free to attach the JDHCP trace when you're done capturing.