We have a problem with additional routes and pxe booting.

Client subnet 192.168.48.0/21
Server subnet 192.168.15.0/24 (with the ZEN servers)
The gateway for the server subnet is 192.168.48.2
The default gateway for internet is 192.168.55.254 (is in client subnet)

If we configure the dhcp server with default GW to 192.168.48.2 then the pxe process goes at normal speed (Directly loading zmaint.cfg en further the progress dots)
If we configure the dhcp server with default GW 192.168.55.254 and a additional route 192.168.15.0 tot 192.168.48.2 (option 121 classless static route) then a windows client works fine but the PXE boot is very slow (5 minute zmaint.cfg in display and then loading pxelinux.cfg files every 5 minutes another)

Does the pxe boot not support static routes given by dhcp?