If you have a PXE server with multiple interfaces and there is no routing between the networks it is possible to run multiple instances of the PXE server, on Unix. This issue is that PXE can only hand out 1 tftp server per instance.
Install the PXE Server
Run the 'OM<version>-<platform>.SH -local'
Choose an install directory of /usr/local/pxe-1
Install only the PXE Component
Repeat this for each NIC you will run PXE on
Setup the Startup Scripts
Copy the /usr/local/pxe-1/conf/blpxe to /etc/init.d/blpxe-1
On RedHat run chkconfig --add blpxe-1
Repeat for other installs
Modify the Configuration
For all PXE instances modify the <install dir>/br/pxe.conf file
Change the multicast_address to match the IP of the interface to listen on
Change the interface to match the ethernet device to bind to
Change the tftp_server_address to match the address of the tftp server on this network
Run the following blasadmin commands against each pxe install (use the blasadmin binary in <install dir>/br/blasadmin)
blasadmin -s _pxe set AppServer RegistryPort 9908
blasadmin -s _pxe set AppServer MaxPort 9955
blasadmin -s _pxe set AppServer MinPort 9950
The numbers used above must be unique for each instance. So for another instance I would use 9909, 10055 and 10050 respectively.
Startup the Services