What version of LDMS / EPM are you on?
Around 2016.3 (if I'm not mistaken), we introduced a self-electing option for PXE reps (to ensure that if even a dedicated box goes down, "someone else" can go on carry the torch).
Otherwise, our PXE reps are primarily made so you DON'T have to reconfigure your routers. There's a few DHCP options you may want to look at though here -- How to configure DHCP to work with LANDESK PXE boot -- !
And you may generally want to study a few of the BKM's from the OS Provisioning landin page -- OS Deployment and Provisioning -- here.
Also - moving this thread over into OS Provisioning section, since't it's not really related to agent deployment.
That should help you a bit .