I want to set up pxe/tftp server in my network. I already have a dhcp server on my isp router wich has dhcp option 60 and dhcp option 240. I nee to know if can i set it up in order to lease pxe info (tftp server and boot) or i need to set up a brand new dhcp with dnsmasq. In case i need to set up a new dhcp server i need to know if both can be up at time or i must deactivate the older one. So i need to know if the new one can be configured ony for pxe lease info and maintain the original one as long as it has be working until now. Thanks.
You have 2 options
Setting your ISP router as a PXE server by adding options 66 & 67 or the fields file and next_server if available
Leaving the ISP DHCP server untouched and use an additional DHCP server like i.e. dnsmask set as proxyDHCP. In this case your ISP DHCP will only provide IP information to every booting device while the proxyDHCP will provide PXE information "only" to booting PXE clients.
Some ISP routers are not really flexible for setting up a PXE environment then option 2 is always your best choice.
By all means avoid MAC filters and the like they are a mess and will lead you to hard to troubleshoot scenarios.